edit requisition recalculates the approval hierarchy

Hi All,

We are facing an issue in requisition approval process.

The issue is at the time of requisition creation user manually updated the system generated approval hierarchy by clicking "Manage Approval" button and then selecting change managerial hierarchy.

But when one of the approver tries to update the requisition by using "edit requisition" link of notification and do approver checkout the system automatically regenerates/recalculates the approval hierarchy.

How to prevent this ?

Thanks & Regards,

Pratik