Revision already exists with the same key

What causes this issue?

While adding a revision, you entered a key that already exists in the
database. However, this entry is displayed only in display mode in this
system and not in change mode, since no change authorization exists for
this revision in the current system.

System Response

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

How to fix this error?

Specify a different key or remove the entry using the <LS>Skip</>
function.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.