Naming rule &1 is already being used. Change was cancelled

What causes this issue?

Naming rule &V1& has already been used in an update. You can no longer
change it.

System Response

The relevant Fields are reset to their original status.

How to fix this error?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.