Thanks. I am just using the revit addin template. This is in Command.cs
{ [Transaction(TransactionMode.Manual)] public class Command : IExternalCommand { public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements) { UIApplication uiapp = commandData.Application; UIDocument uidoc = uiapp.ActiveUIDocument; Application app = uiapp.Application; Document doc = uidoc.Document; var keyTable = KeynoteTable.GetKeynoteTable(doc); var keys = keyTable.GetKeyBasedTreeEntries(); var entity = keys.FindEntry("3"); var schema = keyTable.GetEntitySchemaGuids(); //var delete = keyTable.DeleteEntity(); return Result.Succeeded; } } }