&1 "&2" cannot be edited anymore

What causes this issue?

Possible causes for this are:
The status of the appraisal is <ls>Completed</>, <ls>Approved</> or
<ls>Rejected</> - this means that you can make no further changes to
it.
You are not allowed to reset the status of the appraisal to <ls>In
process</> for this specific appraisal model.

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?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.