You can adjust the setting for “Allow Changes after Authorization” in the Amount Conditions section of Purchase Order Authorization Rule.

Options are “Within Order Amount” or “Within Limit of Authorizer”. If you only want users to change the purchase group, I suggest “Within Order Amount”.

Amount conditions and Authorizations are not going to affect the ability to change Purchase Group.

You’ve mentioned exactly why the Purchase Group is changed based on the purchase order status, it affects the posting controls.  The purchase order change order requirement is set per site or per supplier or both.  Since it apparently set for one or the other, you can’t get around using the purchase order change order to make this change other than turning it off.

I never understood why purchase order change orders are often so resisted by users.  In reality, change orders can be done in less than a couple of minutes and all the traceability of what was changed is recorded automatically.  The change order trail is there exactly for history and revision purposes.  If there is an intention not to use it, don’t turn it on, however if it is on, it is on because someone is sure that that there is a reason to track why the POs are being changed.  Are they wrong in the first instance?  Is there some other loose process that is contributing to the changes?

Just trying to get around the requirement doesn’t really get to the root of why the change is needed in the first place.  Maybe the data needs corrected BEFORE it ever appears on the purchase order which would prevent the need for the change in this instance.

We do enforce the use of change orders, and I agree, it is just plain good business practice.  However, for some human error reason the Buyer inadvertently selected the incorrect purchase group and the PO was a rush, and unfortunately it was not noticed until after the fact.  I was only asking if it was completely necessary to make this one correction without the CO process occurring, not to correct any cost, supplier, or other more important things that are far more important for change orders and history logging.