diff --git a/libraries/Microsoft.Bot.Builder.Dialogs.Adaptive.Testing/TestScript.cs b/libraries/Microsoft.Bot.Builder.Dialogs.Adaptive.Testing/TestScript.cs
index 503e563007..4c8cc9e424 100644
--- a/libraries/Microsoft.Bot.Builder.Dialogs.Adaptive.Testing/TestScript.cs
+++ b/libraries/Microsoft.Bot.Builder.Dialogs.Adaptive.Testing/TestScript.cs
@@ -202,10 +202,12 @@ await adapter.ProcessActivityAsync(
             DialogManager dm;
             if (callback == null)
             {
-                dm = new DialogManager(Dialog)
+                dm = new DialogManager()
                     .UseResourceExplorer(resourceExplorer)
                     .UseLanguageGeneration();
 
+                dm.RootDialog = Dialog;
+
                 if (LanguagePolicy != null)
                 {
                     dm.UseLanguagePolicy(LanguagePolicy);
diff --git a/libraries/Microsoft.Bot.Builder.Dialogs/DialogManager.cs b/libraries/Microsoft.Bot.Builder.Dialogs/DialogManager.cs
index 8ef26913d8..e6bf159b9b 100644
--- a/libraries/Microsoft.Bot.Builder.Dialogs/DialogManager.cs
+++ b/libraries/Microsoft.Bot.Builder.Dialogs/DialogManager.cs
@@ -23,7 +23,6 @@ public class DialogManager
         private const string LastAccess = "_lastAccess";
         private string _rootDialogId;
         private readonly string _dialogStateProperty;
-        private readonly object _lock = new object();
 
         /// <summary>
         /// Initializes a new instance of the <see cref="DialogManager"/> class.
@@ -70,7 +69,34 @@ public DialogManager(Dialog rootDialog = null, string dialogStateProperty = null
         /// <value>
         /// Root dialog to use to start conversation.
         /// </value>
-        public Dialog RootDialog { get; set; }
+        public Dialog RootDialog
+        {
+            get
+            {
+                if (_rootDialogId != null)
+                {
+                    return Dialogs.Find(_rootDialogId);
+                }
+
+                return null;
+            }
+
+            set
+            {
+                Dialogs = new DialogSet();
+                if (value != null)
+                {
+                    _rootDialogId = value.Id;
+                    Dialogs.TelemetryClient = value.TelemetryClient;
+                    Dialogs.Add(value);
+                    RegisterContainerDialogs(RootDialog, registerRoot: false);
+                }
+                else
+                {
+                    _rootDialogId = null;
+                }
+            }
+        }
 
         /// <summary>
         /// Gets or sets global dialogs that you want to have be callable.
@@ -103,21 +129,6 @@ public DialogManager(Dialog rootDialog = null, string dialogStateProperty = null
         /// <returns>result of the running the logic against the activity.</returns>
         public async Task<DialogManagerResult> OnTurnAsync(ITurnContext context, CancellationToken cancellationToken = default)
         {
-            // Lazy initialize rootdialog so it can refer to assets like LG function templates
-            if (_rootDialogId == null)
-            {
-                lock (_lock)
-                {
-                    if (_rootDialogId == null)
-                    {
-                        _rootDialogId = RootDialog.Id;
-                        Dialogs.TelemetryClient = RootDialog.TelemetryClient;
-                        Dialogs.Add(RootDialog);
-                        RegisterContainerDialogs(RootDialog, registerRoot: false);
-                    }
-                }
-            }
-
             var botStateSet = new BotStateSet();
 
             // Preload TurnState with DM TurnState.