You cannot add new items or influence the approval of PR &

What causes this issue?

Using this option, you can edit the details of a purchase requisition.

System Response

While editing you cannot add new items to the PR. The status of items in
the purchase requisition or the approval process defined for the
purchase requisition will remain the same as it was before editing.

How to fix this error?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.