Diagnosis
You want to create your own layout or object. To prevent current orfuture collision with SAP objects, start your layout or object with aspecial character, a "Y," or a "Z." No SAP layouts or objects with namerange are included in the standard SAP System.
You can overwrite a SAP object manually in this Customizing step. Ifyou do so, you must create a customer object with the name of an SAPobject.

System Response
The system validates whether a definition can be overwritten whenapplicable.