Purchase order already paid on but still in approval status

We have a PO that was originally put in last December and paid and finalized with year end.  Yesterday had a change order added to this PO which sent it back to approval  process.  but we can not dispatch it since original PO is already closed on.  We cancelled the change order items and created a new PO but ORIGINAL PO is stuck in approved status and cant be dispatched or cancelled.  any ideas?