Hi Pran,
Yes, your request can be done by PHAP_ADMIN_PA (not by PHAP_CHANGE, as was suggested here).
The reason you got that error message is that you have tried to set the execution end-date earlier than the current date, and that makes no sense.
As you may know, the execution period determines the period in which the appraisers will be able to enter the appraisal document the perform the appraisal (edit the document). if you set it to a period in the past, what will you gain by doing it?
Just fix the execution period.
Regards,
Liran