public void SetDefinition( 
   CIMEditingTemplate definition
)

await QueuedTask.Run(() =>
      {
        var templateName = "Distribution"; // name of the template to update
        var toolDamlPlugInID = "esri_editing_SketchTwoPointLineTool"; // DAML ID of the tool to set as default
        var toolContentGUID = "e2096d13-b437-4bc1-94ea-4494c3260f72"; // Example GUID, replace with actual GUID from DAML
                                                                      // retrieve the edit template form the layer by name
        var template = featureLayer?.GetTemplate(templateName) as EditingTemplate;
        // get the definition of the layer
        var layerDef = featureLayer?.GetDefinition() as CIMFeatureLayer;
        if (template == null || layerDef == null)
          return;
        if (template.DefaultToolID != toolDamlPlugInID)
        {
          bool updateLayerDef = false;
          if (layerDef.AutoGenerateFeatureTemplates)
          {
            layerDef.AutoGenerateFeatureTemplates = false;
            updateLayerDef = true;
          }

          // retrieve the CIM edit template definition
          var templateDef = template.GetDefinition();

          // assign the GUID from the tool DAML definition, for example
          // <tool id="TestConstructionTool_SampleSDKTool" categoryRefID="esri_editing_construction_polyline" ….>
          //   <tooltip heading="">Tooltip text<disabledText /></tooltip>
          //   <content guid="e58239b3-9c69-49e5-ad4d-bb2ba29ff3ea" />
          // </tool>
          // then the toolContentGUID would be "e58239b3-9c69-49e5-ad4d-bb2ba29ff3ea"

          //templateDef.ToolProgID = toolContentGUID;
          templateDef.DefaultToolGUID = toolContentGUID;

          // set the definition back to 
          template.SetDefinition(templateDef);

          // update the layer definition too
          if (updateLayerDef)
            featureLayer.SetDefinition(layerDef);
        }
      });

// Updates the definition of a specified table template by modifying its name and description.
var table = activeMap.GetStandaloneTablesAsFlattenedList().FirstOrDefault();
await QueuedTask.Run(() =>
  {
    // get a table template
    var tableTemplate = table.GetTemplate("Template1") ?? throw new Exception("No table template named 'Template1' found");
    // get the definition
    var definition = tableTemplate.GetDefinition();
    definition.Description = "New definition";
    definition.Name = "New name";
    // update the definition
    tableTemplate.SetDefinition(definition);
  });