diff --git a/COMET.Web.Common/Extensions/SessionServiceExtensions.cs b/COMET.Web.Common/Extensions/SessionServiceExtensions.cs
new file mode 100644
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+++ b/COMET.Web.Common/Extensions/SessionServiceExtensions.cs
@@ -0,0 +1,108 @@
+// --------------------------------------------------------------------------------------------------------------------
+//  <copyright file="SessionServiceExtensions.cs" company="RHEA System S.A.">
+//     Copyright (c) 2023 RHEA System S.A.
+// 
+//     Authors: Sam Gerené, Alex Vorobiev, Alexander van Delft, Jaime Bernar, Théate Antoine
+// 
+//     This file is part of COMET WEB Community Edition
+//     The COMET WEB Community Edition is the RHEA Web Application implementation of ECSS-E-TM-10-25 Annex A and Annex C.
+// 
+//     The COMET WEB Community Edition is free software; you can redistribute it and/or
+//     modify it under the terms of the GNU Affero General Public
+//     License as published by the Free Software Foundation; either
+//     version 3 of the License, or (at your option) any later version.
+// 
+//     The COMET WEB Community Edition is distributed in the hope that it will be useful,
+//     but WITHOUT ANY WARRANTY; without even the implied warranty of
+//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//    Affero General Public License for more details.
+// 
+//    You should have received a copy of the GNU Affero General Public License
+//    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//  </copyright>
+//  --------------------------------------------------------------------------------------------------------------------
+
+namespace COMET.Web.Common.Extensions
+{
+    using CDP4Common.EngineeringModelData;
+    using CDP4Common.SiteDirectoryData;
+
+    using COMET.Web.Common.Services.SessionManagement;
+
+    using FluentResults;
+
+    /// <summary>
+    /// Static class with extension methods for the <see cref="ISessionService"/>
+    /// </summary>
+    public static class SessionServiceExtensions
+    {
+        /// <summary>
+        /// Marks a top element for a given iteration
+        /// </summary>
+        /// <param name="sessionService">The <see cref="ISessionService"/> in which the iteration will be updated</param>
+        /// <param name="iteration">The <see cref="Iteration"/> to be updated</param>
+        /// <param name="element">The <see cref="ElementDefinition"/> to be marked as top element</param>
+        /// <returns>A <see cref="Task"/></returns>
+        /// <exception cref="ArgumentNullException">Throws an <see cref="ArgumentException"/></exception>
+        public static async Task<Result> MarkTopElement(this ISessionService sessionService, Iteration iteration, ElementDefinition element)
+        {
+            if (iteration == null)
+            {
+                throw new ArgumentNullException(nameof(iteration));
+            }
+
+            var iterationClone = iteration.Clone(false);
+            iterationClone.TopElement = element;
+
+            return await sessionService.UpdateThing(iteration.Container, iterationClone);
+        }
+
+        /// <summary>
+        /// Adds a new parameter for a given element definition
+        /// </summary>
+        /// <param name="sessionService">The <see cref="ISessionService"/> in which data will be updated</param>
+        /// <param name="elementDefinition">The <see cref="ElementDefinition"/> in which a new parameter will be added</param>
+        /// <param name="group">The <see cref="ParameterGroup"/> of the new parameter</param>
+        /// <param name="parameterType">The <see cref="ParameterType"/> of the new parameter</param>
+        /// <param name="measurementScale">The <see cref="MeasurementScale"/> of the new parameter</param>
+        /// <param name="owner">The <see cref="DomainOfExpertise"/> of the owner</param>
+        /// <returns>A <see cref="Task"/></returns>
+        /// <exception cref="ArgumentNullException">Throws an <see cref="ArgumentNullException"/></exception>
+        public static async Task<Result> AddParameter(this ISessionService sessionService, ElementDefinition elementDefinition, ParameterGroup group, ParameterType parameterType, MeasurementScale measurementScale, DomainOfExpertise owner)
+        {
+            if (elementDefinition == null)
+            {
+                throw new ArgumentNullException(nameof(elementDefinition), "The container ElementDefinition may not be null");
+            }
+
+            if (parameterType == null)
+            {
+                throw new ArgumentNullException(nameof(parameterType), "The ParameterType may not be null");
+            }
+
+            if (owner == null)
+            {
+                throw new ArgumentNullException(nameof(owner), "The owner DomainOfExpertise may not be null");
+            }
+
+            if (sessionService.Session == null)
+            {
+                throw new ArgumentNullException(nameof(sessionService.Session), "The session may not be null");
+            }
+
+            var parameter = new Parameter(Guid.NewGuid(), null, null)
+            {
+                Owner = owner,
+                ParameterType = parameterType,
+                Scale = measurementScale,
+                Group = group,
+                ValueSet = { new ParameterValueSet() }
+            };
+
+            var clone = elementDefinition.Clone(false);
+            clone.Parameter.Add(parameter);
+
+            return await sessionService.CreateThing(clone, parameter);
+        }
+    }
+}