Changing requester on Purchase Order submits PO for approval

Summary

Is there a set up that prevents PO going for approval if only requester is updated?

Content

There are cases where the buyer needs to change the requester on the Purchase Order.

If we edit the PO and only change the requester name (no amounts or anything else), the PO still goes for approval to the approver. This kind of changes should be automatically approved.

Is this system behaviour or can we change something in the set up to get these changes automatically approved (without creating a bunch of new rules)

Thanks!

-Minna