import arcpy, os # 1. Get parameter values AnnoLayer = 'Anno0200Scale' #2. Set Map Layers and default paths thisProject = arcpy.mp.ArcGISProject("CURRENT") Map = thisProject.activeMap AnnoLyr = Map.listLayers(AnnoLayer)[0] FolderPath = thisProject.homeFolder arcpy.AddMessage ("Map: " + Map.name) arcpy.AddMessage (AnnoLyr.dataSource) datasource = AnnoLyr.dataSource lastslash = datasource.rfind("/") workspace = datasource[:lastslash] arcpy.AddMessage(workspace) MapNumber = 'XXXX' # do edit session (Comment it out if you do not want to use it edit = arcpy.da.Editor(workspace) edit.startEditing(with_undo=False, multiuser_mode=True) edit.startOperation() with arcpy.da.UpdateCursor(AnnoLyr, ["MapNumber"],"OBJECTID = 7695") as cursor: for row in cursor: row[0] = MapNumber cursor.updateRow(row) edit.stopOperation() edit.stopEditing(save_changes=True)