Zero Price Indicator on Requisition Detail Line

We are implementing FSCM 9.2.

When creating a requisition in eProcurement, the requestor selects and adds an item to the requisition line and then the requestor goes to the Requisition Line Details page and finds that the Zero Price Indicator

check box is grayed out. Is there a way to ungray this check box so that when creating the requisition, the requestor has an option to check or not check the zero price indicator box. Will appreciate

any help in resolving this issue.