If you received something and accepted it, but later realize you need to return it for some reason, you have to do create a sales order back to the supplier as well as do an outgoing transfer.

You won't be able to edit the purchase order like you could in the pre-Metrc days because then it would not sync with an incoming transfer.

Since there is no cultivation tax tracking in Distru, you will have to track the tax implications of returning something to a supplier. 

Also if you do this, please make sure the incoming transfer was synced to a PO (or if it were a broken transfer, then make sure the packages were imported) BEFORE you send it out again.