How to return an item to a subcontractor for repair
In DBA, subcontract work is done via a Job, linked to a subcontract PO. With this design, you're not actually receiving the item from the PO, in DBA, but are instead receiving the subcontract cost, which flows into the Job.
So, in the scenario where you receive something back from the subcontractor but find that it needs to be sent back for repair, you're essentially returning the "subcontract cost" to the supplier (since no actual sending or receiving of an item number actually happens with subcontracting in DBA).
To return this cost, you'll need to first reopen the Job if it's already closed. With the Job open, you'll then need to reopen the subcontract PO and the PO line itself. The PO can be reopened in the 'Header' tab of the PO and the line can be reopened in the 'Details' tab of the PO ('Line Status' column). After that, you should be able to access the PO Receipts screen, highlight the line, click the 'Transactions' sub-tab and perform the reversal. This pulls the cost from the Job and returns it. Then, whenever you receive the item back, you need to re-enter the PO Receipt for the subcontract service. This cost should flow back into the Job.
Something to be aware of is that, with DBA, no actual item is being purchased from the subcontract supplier. It's the subcontract cost that DBA cares about. So, if the repair is at no cost, then you really don't even have to enter anything into DBA for the repair, because it will have no effect on the overall outcome. So, it's up to you whether or not you wish to perform the above process for tracking purposes (you'll be able to see something is "outstanding" and awaiting further receipt, which can be helpful).