PO change order solution

HI. We have a high po hierarchy. Sometimes there are change orders against a PO which has already gone thru the approval, and there is a reason to add more funds to the PO, then the PO goes thru the entire hierarchy chain again.
Wanted to know in order to get around to this, is the change to workflow the only option or is there anything out of the box in purchasing available.

Thanks.

Komal