diff --git a/src/datanode/src/alive_keeper.rs b/src/datanode/src/alive_keeper.rs
index c6ef6cb3f6db..a1c1788827c9 100644
--- a/src/datanode/src/alive_keeper.rs
+++ b/src/datanode/src/alive_keeper.rs
@@ -129,8 +129,10 @@ impl RegionAliveKeeper {
         let request = RegionRequest::Close(RegionCloseRequest {});
         if let Err(e) = self.region_server.handle_request(region_id, request).await {
             if e.status_code() != StatusCode::RegionNotFound {
-                let _ = self.region_server.set_writable(region_id, false);
-                error!(e; "Failed to close staled region {}, set region to readonly.",region_id);
+                let _ = self
+                    .region_server
+                    .set_region_role(region_id, RegionRole::Follower);
+                error!(e; "Failed to close staled region {}, convert region to readonly.",region_id);
             }
         }
     }
@@ -378,7 +380,7 @@ impl CountdownTask {
                             }
                         },
                         Some(CountdownCommand::Reset((role, deadline))) => {
-                            let _ = self.region_server.set_writable(self.region_id, role.writable());
+                            let _ = self.region_server.set_region_role(self.region_id, role);
                             trace!(
                                 "Reset deadline of region {region_id} to approximately {} seconds later.",
                                 (deadline - Instant::now()).as_secs_f32(),
@@ -399,8 +401,8 @@ impl CountdownTask {
                     }
                 }
                 () = &mut countdown => {
-                    warn!("The region {region_id} lease is expired, set region to readonly.");
-                    let _ = self.region_server.set_writable(self.region_id, false);
+                    warn!("The region {region_id} lease is expired, convert region to readonly.");
+                    let _ = self.region_server.set_region_role(self.region_id, RegionRole::Follower);
                     // resets the countdown.
                     let far_future = Instant::now() + Duration::from_secs(86400 * 365 * 30);
                     countdown.as_mut().reset(far_future);
@@ -436,7 +438,9 @@ mod test {
             .handle_request(region_id, RegionRequest::Create(builder.build()))
             .await
             .unwrap();
-        region_server.set_writable(region_id, true).unwrap();
+        region_server
+            .set_region_role(region_id, RegionRole::Leader)
+            .unwrap();
 
         // Register a region before starting.
         alive_keeper.register_region(region_id).await;
diff --git a/src/datanode/src/datanode.rs b/src/datanode/src/datanode.rs
index 149aa44ebe34..1d14d0e1bab3 100644
--- a/src/datanode/src/datanode.rs
+++ b/src/datanode/src/datanode.rs
@@ -47,7 +47,7 @@ use servers::server::ServerHandlers;
 use servers::Mode;
 use snafu::{ensure, OptionExt, ResultExt};
 use store_api::path_utils::{region_dir, WAL_DIR};
-use store_api::region_engine::RegionEngineRef;
+use store_api::region_engine::{RegionEngineRef, RegionRole};
 use store_api::region_request::RegionOpenRequest;
 use store_api::storage::RegionId;
 use tokio::fs;
@@ -543,9 +543,9 @@ async fn open_all_regions(
 
     for region_id in open_regions {
         if open_with_writable {
-            if let Err(e) = region_server.set_writable(region_id, true) {
+            if let Err(e) = region_server.set_region_role(region_id, RegionRole::Leader) {
                 error!(
-                    e; "failed to set writable for region {region_id}"
+                    e; "failed to convert region {region_id} to leader"
                 );
             }
         }
diff --git a/src/datanode/src/heartbeat/handler.rs b/src/datanode/src/heartbeat/handler.rs
index d23615eb13d8..3099ec281f5b 100644
--- a/src/datanode/src/heartbeat/handler.rs
+++ b/src/datanode/src/heartbeat/handler.rs
@@ -153,6 +153,7 @@ mod tests {
     use mito2::engine::MITO_ENGINE_NAME;
     use mito2::test_util::{CreateRequestBuilder, TestEnv};
     use store_api::path_utils::region_dir;
+    use store_api::region_engine::RegionRole;
     use store_api::region_request::{RegionCloseRequest, RegionRequest};
     use store_api::storage::RegionId;
     use tokio::sync::mpsc::{self, Receiver};
@@ -295,7 +296,9 @@ mod tests {
             }
 
             assert_matches!(
-                region_server.set_writable(region_id, true).unwrap_err(),
+                region_server
+                    .set_region_role(region_id, RegionRole::Leader)
+                    .unwrap_err(),
                 error::Error::RegionNotFound { .. }
             );
         }
diff --git a/src/datanode/src/heartbeat/handler/downgrade_region.rs b/src/datanode/src/heartbeat/handler/downgrade_region.rs
index 4ca6e39a22b7..7f39d8c655fb 100644
--- a/src/datanode/src/heartbeat/handler/downgrade_region.rs
+++ b/src/datanode/src/heartbeat/handler/downgrade_region.rs
@@ -56,7 +56,7 @@ impl HandlerContext {
         }: DowngradeRegion,
     ) -> BoxFuture<'static, InstructionReply> {
         Box::pin(async move {
-            let Some(writable) = self.region_server.is_writable(region_id) else {
+            let Some(writable) = self.region_server.is_region_leader(region_id) else {
                 return InstructionReply::DowngradeRegion(DowngradeRegionReply {
                     last_entry_id: None,
                     exists: false,
diff --git a/src/datanode/src/heartbeat/handler/upgrade_region.rs b/src/datanode/src/heartbeat/handler/upgrade_region.rs
index 0d1ef0476c95..9acb3da9c348 100644
--- a/src/datanode/src/heartbeat/handler/upgrade_region.rs
+++ b/src/datanode/src/heartbeat/handler/upgrade_region.rs
@@ -31,7 +31,7 @@ impl HandlerContext {
         }: UpgradeRegion,
     ) -> BoxFuture<'static, InstructionReply> {
         Box::pin(async move {
-            let Some(writable) = self.region_server.is_writable(region_id) else {
+            let Some(writable) = self.region_server.is_region_leader(region_id) else {
                 return InstructionReply::UpgradeRegion(UpgradeRegionReply {
                     ready: false,
                     exists: false,
diff --git a/src/datanode/src/region_server.rs b/src/datanode/src/region_server.rs
index 47e4f553bc10..1152667bd1a7 100644
--- a/src/datanode/src/region_server.rs
+++ b/src/datanode/src/region_server.rs
@@ -254,8 +254,7 @@ impl RegionServer {
             .collect()
     }
 
-    pub fn is_writable(&self, region_id: RegionId) -> Option<bool> {
-        // TODO(weny): Finds a better way.
+    pub fn is_region_leader(&self, region_id: RegionId) -> Option<bool> {
         self.inner.region_map.get(&region_id).and_then(|engine| {
             engine.role(region_id).map(|role| match role {
                 RegionRole::Follower => false,
@@ -264,14 +263,14 @@ impl RegionServer {
         })
     }
 
-    pub fn set_writable(&self, region_id: RegionId, writable: bool) -> Result<()> {
+    pub fn set_region_role(&self, region_id: RegionId, role: RegionRole) -> Result<()> {
         let engine = self
             .inner
             .region_map
             .get(&region_id)
             .with_context(|| RegionNotFoundSnafu { region_id })?;
         engine
-            .set_writable(region_id, writable)
+            .set_region_role(region_id, role)
             .with_context(|_| HandleRegionRequestSnafu { region_id })
     }
 
@@ -790,7 +789,7 @@ impl RegionServerInner {
                 info!("Region {region_id} is deregistered from engine {engine_type}");
                 self.region_map
                     .remove(&region_id)
-                    .map(|(id, engine)| engine.set_writable(id, false));
+                    .map(|(id, engine)| engine.set_region_role(id, RegionRole::Follower));
                 self.event_listener.on_region_deregistered(region_id);
             }
             RegionChange::Catchup => {
diff --git a/src/datanode/src/tests.rs b/src/datanode/src/tests.rs
index 95ccfce29fb2..229c4805ecaf 100644
--- a/src/datanode/src/tests.rs
+++ b/src/datanode/src/tests.rs
@@ -220,7 +220,7 @@ impl RegionEngine for MockRegionEngine {
         Ok(())
     }
 
-    fn set_writable(&self, _region_id: RegionId, _writable: bool) -> Result<(), BoxedError> {
+    fn set_region_role(&self, _region_id: RegionId, _role: RegionRole) -> Result<(), BoxedError> {
         Ok(())
     }
 
diff --git a/src/file-engine/src/engine.rs b/src/file-engine/src/engine.rs
index 038a2ccd801a..bb31ad1e694a 100644
--- a/src/file-engine/src/engine.rs
+++ b/src/file-engine/src/engine.rs
@@ -113,9 +113,9 @@ impl RegionEngine for FileRegionEngine {
         None
     }
 
-    fn set_writable(&self, region_id: RegionId, writable: bool) -> Result<(), BoxedError> {
+    fn set_region_role(&self, region_id: RegionId, role: RegionRole) -> Result<(), BoxedError> {
         self.inner
-            .set_writable(region_id, writable)
+            .set_region_role(region_id, role)
             .map_err(BoxedError::new)
     }
 
@@ -190,7 +190,7 @@ impl EngineInner {
         Ok(())
     }
 
-    fn set_writable(&self, _region_id: RegionId, _writable: bool) -> EngineResult<()> {
+    fn set_region_role(&self, _region_id: RegionId, _region_role: RegionRole) -> EngineResult<()> {
         // TODO(zhongzc): Improve the semantics and implementation of this API.
         Ok(())
     }
diff --git a/src/metric-engine/src/engine.rs b/src/metric-engine/src/engine.rs
index 407e81a12c66..7f02300a0846 100644
--- a/src/metric-engine/src/engine.rs
+++ b/src/metric-engine/src/engine.rs
@@ -201,14 +201,14 @@ impl RegionEngine for MetricEngine {
         Ok(())
     }
 
-    fn set_writable(&self, region_id: RegionId, writable: bool) -> Result<(), BoxedError> {
+    fn set_region_role(&self, region_id: RegionId, role: RegionRole) -> Result<(), BoxedError> {
         // ignore the region not found error
         for x in [
             utils::to_metadata_region_id(region_id),
             utils::to_data_region_id(region_id),
             region_id,
         ] {
-            if let Err(e) = self.inner.mito.set_writable(x, writable)
+            if let Err(e) = self.inner.mito.set_region_role(x, role)
                 && e.status_code() != StatusCode::RegionNotFound
             {
                 return Err(e);
diff --git a/src/mito2/src/engine.rs b/src/mito2/src/engine.rs
index 7cac84af616b..60a2a97848a0 100644
--- a/src/mito2/src/engine.rs
+++ b/src/mito2/src/engine.rs
@@ -440,14 +440,14 @@ impl EngineInner {
         Ok(scan_region)
     }
 
-    /// Set writable mode for a region.
-    fn set_writable(&self, region_id: RegionId, writable: bool) -> Result<()> {
+    /// Converts the [`RegionRole`].
+    fn set_region_role(&self, region_id: RegionId, role: RegionRole) -> Result<()> {
         let region = self
             .workers
             .get_region(region_id)
             .context(RegionNotFoundSnafu { region_id })?;
 
-        region.set_writable(writable);
+        region.set_region_role(role);
         Ok(())
     }
 
@@ -560,9 +560,9 @@ impl RegionEngine for MitoEngine {
         size.try_into().ok()
     }
 
-    fn set_writable(&self, region_id: RegionId, writable: bool) -> Result<(), BoxedError> {
+    fn set_region_role(&self, region_id: RegionId, role: RegionRole) -> Result<(), BoxedError> {
         self.inner
-            .set_writable(region_id, writable)
+            .set_region_role(region_id, role)
             .map_err(BoxedError::new)
     }
 
diff --git a/src/mito2/src/engine/alter_test.rs b/src/mito2/src/engine/alter_test.rs
index b48dc2ccfb08..2e75bf19faa0 100644
--- a/src/mito2/src/engine/alter_test.rs
+++ b/src/mito2/src/engine/alter_test.rs
@@ -24,7 +24,7 @@ use common_recordbatch::RecordBatches;
 use datatypes::prelude::ConcreteDataType;
 use datatypes::schema::ColumnSchema;
 use store_api::metadata::ColumnMetadata;
-use store_api::region_engine::RegionEngine;
+use store_api::region_engine::{RegionEngine, RegionRole};
 use store_api::region_request::{
     AddColumn, AddColumnLocation, AlterKind, RegionAlterRequest, RegionOpenRequest, RegionRequest,
 };
@@ -213,8 +213,10 @@ async fn test_put_after_alter() {
         )
         .await
         .unwrap();
-    // Set writable.
-    engine.set_writable(region_id, true).unwrap();
+    // Convert region to leader.
+    engine
+        .set_region_role(region_id, RegionRole::Leader)
+        .unwrap();
 
     // Put with old schema.
     let rows = Rows {
diff --git a/src/mito2/src/engine/catchup_test.rs b/src/mito2/src/engine/catchup_test.rs
index 36c41299bb3b..9ebbbbd6a023 100644
--- a/src/mito2/src/engine/catchup_test.rs
+++ b/src/mito2/src/engine/catchup_test.rs
@@ -22,7 +22,7 @@ use common_recordbatch::RecordBatches;
 use common_wal::options::{KafkaWalOptions, WalOptions, WAL_OPTIONS_KEY};
 use rstest::rstest;
 use rstest_reuse::{self, apply};
-use store_api::region_engine::{RegionEngine, SetRegionRoleStateResponse};
+use store_api::region_engine::{RegionEngine, RegionRole, SetRegionRoleStateResponse};
 use store_api::region_request::{RegionCatchupRequest, RegionOpenRequest, RegionRequest};
 use store_api::storage::{RegionId, ScanRequest};
 
@@ -247,7 +247,7 @@ async fn test_catchup_with_incorrect_last_entry_id(factory: Option<LogStoreFacto
     assert_matches!(err, error::Error::UnexpectedReplay { .. });
 
     // It should ignore requests to writable regions.
-    region.set_writable(true);
+    region.set_region_role(RegionRole::Leader);
     let resp = follower_engine
         .handle_request(
             region_id,
diff --git a/src/mito2/src/engine/compaction_test.rs b/src/mito2/src/engine/compaction_test.rs
index e19f95088c46..7951331b20d9 100644
--- a/src/mito2/src/engine/compaction_test.rs
+++ b/src/mito2/src/engine/compaction_test.rs
@@ -19,7 +19,7 @@ use api::v1::{ColumnSchema, Rows};
 use common_recordbatch::{RecordBatches, SendableRecordBatchStream};
 use datatypes::prelude::ScalarVector;
 use datatypes::vectors::TimestampMillisecondVector;
-use store_api::region_engine::RegionEngine;
+use store_api::region_engine::{RegionEngine, RegionRole};
 use store_api::region_request::{
     RegionCompactRequest, RegionDeleteRequest, RegionFlushRequest, RegionRequest,
 };
@@ -302,8 +302,10 @@ async fn test_readonly_during_compaction() {
     // Waits until the engine receives compaction finished request.
     listener.wait_handle_finished().await;
 
-    // Sets the region to read only mode.
-    engine.set_writable(region_id, false).unwrap();
+    // Converts region to follower.
+    engine
+        .set_region_role(region_id, RegionRole::Follower)
+        .unwrap();
     // Wakes up the listener.
     listener.wake();
 
diff --git a/src/mito2/src/engine/open_test.rs b/src/mito2/src/engine/open_test.rs
index 9e9a9e3486c0..c7ad47535c81 100644
--- a/src/mito2/src/engine/open_test.rs
+++ b/src/mito2/src/engine/open_test.rs
@@ -53,7 +53,9 @@ async fn test_engine_open_empty() {
         .await
         .unwrap_err();
     assert_eq!(StatusCode::RegionNotFound, err.status_code());
-    let err = engine.set_writable(region_id, true).unwrap_err();
+    let err = engine
+        .set_region_role(region_id, RegionRole::Leader)
+        .unwrap_err();
     assert_eq!(StatusCode::RegionNotFound, err.status_code());
     let role = engine.role(region_id);
     assert_eq!(role, None);
@@ -134,8 +136,10 @@ async fn test_engine_open_readonly() {
     assert_eq!(StatusCode::RegionNotReady, err.status_code());
 
     assert_eq!(Some(RegionRole::Follower), engine.role(region_id));
-    // Set writable and write.
-    engine.set_writable(region_id, true).unwrap();
+    // Converts region to leader.
+    engine
+        .set_region_role(region_id, RegionRole::Leader)
+        .unwrap();
     assert_eq!(Some(RegionRole::Leader), engine.role(region_id));
 
     put_rows(&engine, region_id, rows).await;
diff --git a/src/mito2/src/engine/set_readonly_test.rs b/src/mito2/src/engine/set_readonly_test.rs
index 8f18b6c83909..239305bdefa7 100644
--- a/src/mito2/src/engine/set_readonly_test.rs
+++ b/src/mito2/src/engine/set_readonly_test.rs
@@ -15,7 +15,9 @@
 use api::v1::Rows;
 use common_error::ext::ErrorExt;
 use common_error::status_code::StatusCode;
-use store_api::region_engine::{RegionEngine, SetRegionRoleStateResponse, SettableRegionRoleState};
+use store_api::region_engine::{
+    RegionEngine, RegionRole, SetRegionRoleStateResponse, SettableRegionRoleState,
+};
 use store_api::region_request::{RegionPutRequest, RegionRequest};
 use store_api::storage::RegionId;
 
@@ -74,7 +76,9 @@ async fn test_set_readonly_gracefully() {
 
     assert_eq!(error.status_code(), StatusCode::RegionNotReady);
 
-    engine.set_writable(region_id, true).unwrap();
+    engine
+        .set_region_role(region_id, RegionRole::Leader)
+        .unwrap();
 
     put_rows(&engine, region_id, rows).await;
 
diff --git a/src/mito2/src/region.rs b/src/mito2/src/region.rs
index 22637bd846cd..fd900775dd31 100644
--- a/src/mito2/src/region.rs
+++ b/src/mito2/src/region.rs
@@ -29,7 +29,7 @@ use smallvec::{smallvec, SmallVec};
 use snafu::{ensure, OptionExt};
 use store_api::logstore::provider::Provider;
 use store_api::metadata::RegionMetadataRef;
-use store_api::region_engine::SettableRegionRoleState;
+use store_api::region_engine::{RegionRole, SettableRegionRoleState};
 use store_api::storage::RegionId;
 
 use crate::access_layer::AccessLayerRef;
@@ -200,30 +200,33 @@ impl MitoRegion {
         self.manifest_ctx.state.load()
     }
 
-    /// Sets the writable state.
-    pub(crate) fn set_writable(&self, writable: bool) {
-        if writable {
-            // Only sets the region to writable if it is read only.
-            // This prevents others updating the manifest.
-            match self.manifest_ctx.state.compare_exchange(
-                RegionRoleState::Follower,
-                RegionRoleState::Leader(RegionLeaderState::Writable),
-            ) {
-                Ok(state) => info!(
-                    "Set region {} to writable, previous state: {:?}",
-                    self.region_id, state
-                ),
-                Err(state) => {
-                    if state != RegionRoleState::Leader(RegionLeaderState::Writable) {
-                        warn!(
-                            "Failed to set region {} to writable, current state: {:?}",
-                            self.region_id, state
-                        )
+    /// Sets the [`RegionRole`].
+    pub(crate) fn set_region_role(&self, next_role: RegionRole) {
+        match next_role {
+            RegionRole::Follower => {
+                self.manifest_ctx.state.store(RegionRoleState::Follower);
+            }
+            RegionRole::Leader => {
+                // Only sets the region to writable if it is read only.
+                // This prevents others updating the manifest.
+                match self.manifest_ctx.state.compare_exchange(
+                    RegionRoleState::Follower,
+                    RegionRoleState::Leader(RegionLeaderState::Writable),
+                ) {
+                    Ok(state) => info!(
+                        "Convert region {} to leader, previous role state: {:?}",
+                        self.region_id, state
+                    ),
+                    Err(state) => {
+                        if state != RegionRoleState::Leader(RegionLeaderState::Writable) {
+                            warn!(
+                                "Failed to convert region {} to leader, current role state: {:?}",
+                                self.region_id, state
+                            )
+                        }
                     }
                 }
             }
-        } else {
-            self.manifest_ctx.state.store(RegionRoleState::Follower);
         }
     }
 
@@ -301,8 +304,6 @@ impl MitoRegion {
                 }
             }
         }
-
-        self.set_writable(false);
     }
 
     /// Switches the region state to `RegionState::Writable` if the current state is `expect`.
diff --git a/src/mito2/src/region/opener.rs b/src/mito2/src/region/opener.rs
index 822dce95d71f..15465feadba2 100644
--- a/src/mito2/src/region/opener.rs
+++ b/src/mito2/src/region/opener.rs
@@ -28,6 +28,7 @@ use snafu::{ensure, OptionExt};
 use store_api::logstore::provider::Provider;
 use store_api::logstore::LogStore;
 use store_api::metadata::{ColumnMetadata, RegionMetadata};
+use store_api::region_engine::RegionRole;
 use store_api::storage::{ColumnId, RegionId};
 
 use crate::access_layer::AccessLayer;
@@ -171,8 +172,8 @@ impl RegionOpener {
                     &expect.column_metadatas,
                     &expect.primary_key,
                 )?;
-                // To keep consistence with Create behavior, set the opened Region writable.
-                region.set_writable(true);
+                // To keep consistence with Create behavior, set the opened Region to RegionRole::Leader.
+                region.set_region_role(RegionRole::Leader);
                 return Ok(region);
             }
             Ok(None) => {
diff --git a/src/mito2/src/test_util.rs b/src/mito2/src/test_util.rs
index cd449e53fae6..0bd85747c0f1 100644
--- a/src/mito2/src/test_util.rs
+++ b/src/mito2/src/test_util.rs
@@ -52,7 +52,7 @@ use rskafka::client::{Client, ClientBuilder};
 use rskafka::record::Record;
 use rstest_reuse::template;
 use store_api::metadata::{ColumnMetadata, RegionMetadataRef};
-use store_api::region_engine::RegionEngine;
+use store_api::region_engine::{RegionEngine, RegionRole};
 use store_api::region_request::{
     RegionCloseRequest, RegionCreateRequest, RegionDeleteRequest, RegionFlushRequest,
     RegionOpenRequest, RegionPutRequest, RegionRequest,
@@ -1114,6 +1114,8 @@ pub async fn reopen_region(
         .unwrap();
 
     if writable {
-        engine.set_writable(region_id, true).unwrap();
+        engine
+            .set_region_role(region_id, RegionRole::Leader)
+            .unwrap();
     }
 }
diff --git a/src/mito2/src/worker/handle_catchup.rs b/src/mito2/src/worker/handle_catchup.rs
index 505c994d3607..4c7efbde4db8 100644
--- a/src/mito2/src/worker/handle_catchup.rs
+++ b/src/mito2/src/worker/handle_catchup.rs
@@ -20,6 +20,7 @@ use common_telemetry::info;
 use common_telemetry::tracing::warn;
 use snafu::ensure;
 use store_api::logstore::LogStore;
+use store_api::region_engine::RegionRole;
 use store_api::region_request::{AffectedRows, RegionCatchupRequest};
 use store_api::storage::RegionId;
 use tokio::time::Instant;
@@ -112,7 +113,7 @@ impl<S: LogStore> RegionWorkerLoop<S> {
         }
 
         if request.set_writable {
-            region.set_writable(true);
+            region.set_region_role(RegionRole::Leader);
         }
 
         Ok(0)
diff --git a/src/query/src/optimizer/test_util.rs b/src/query/src/optimizer/test_util.rs
index 5e5de855e542..d8b100d1711a 100644
--- a/src/query/src/optimizer/test_util.rs
+++ b/src/query/src/optimizer/test_util.rs
@@ -89,7 +89,7 @@ impl RegionEngine for MetaRegionEngine {
         Ok(())
     }
 
-    fn set_writable(&self, _region_id: RegionId, _writable: bool) -> Result<(), BoxedError> {
+    fn set_region_role(&self, _region_id: RegionId, _role: RegionRole) -> Result<(), BoxedError> {
         unimplemented!()
     }
 
diff --git a/src/store-api/src/region_engine.rs b/src/store-api/src/region_engine.rs
index 42f8aae3f4c1..eebf0d53fba6 100644
--- a/src/store-api/src/region_engine.rs
+++ b/src/store-api/src/region_engine.rs
@@ -307,12 +307,12 @@ pub trait RegionEngine: Send + Sync {
     /// Stops the engine
     async fn stop(&self) -> Result<(), BoxedError>;
 
-    /// Sets writable mode for a region.
+    /// Sets [RegionRole] for a region.
     ///
     /// The engine checks whether the region is writable before writing to the region. Setting
     /// the region as readonly doesn't guarantee that write operations in progress will not
     /// take effect.
-    fn set_writable(&self, region_id: RegionId, writable: bool) -> Result<(), BoxedError>;
+    fn set_region_role(&self, region_id: RegionId, role: RegionRole) -> Result<(), BoxedError>;
 
     /// Sets region role state gracefully.
     ///