Is there a way to override the Supplier details in SCO created from Sales Order

We have a situation where Supplier details are pushed from Upstream Systems and expected to create PR/PO from a Sales Order and supply the goods back to a warehouse.

Any Workaround to update the Supplier details after creation of purchase requisition or before purchase requisition.

I saw the supplier details are not allowed to update on requisition, since the supplier details are suggested in GOP. I saw a note id to override the supplier details for Back to Back Buy but not sure how we can cancel the purchase order created and will allow the requisition to convert into PO for the desired supplier details.