& requisition(s) already changed by other users

What causes this issue?

From within list processing, you wish to change a purchase requisition
that has in the meantime been changed by another user.

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

System Response

How to fix this error?

Check the requisition before making your changes.

Error message extract from SAP system. Copyright SAP SE.