Order closed not able to post GRN

Dear All,

I am facing one problem, i have searched in forum but was not answered.

The user has created the PR with account assignment cat 'F', and the PO is also created.

But when he is creating GRN it is showin an error message  ' GRN for purchase order is not allowed (ORD 5010000000).

When i checked the order, it is maintenence order, the system status is ' CLSD CNF  MACM PRC  SETC ' with  completed (COMP).

I know once the order is closed no GRN can be made. But is there any solution to revoke the status??

Please provide me the solution for the same. Else the user has to create new PR, PO and order.

Regards,

Priti