PO Workflow: Display only while releasing PO

Hi Team,

I want to know if there is a possibility that "Approver should not be able to change the PO data while releasing the PO from the workitem".

Requirement: When the Approver clicks the workitem to release the PO, he is navigated to the transaction to release the PO. At that time he should only be allowed to release the PO and not make any changes in the PO data.

Regards,

Ashish