Mark serial number to repair

Hi! how are you?
I use ERP NEXT to manage a store of electronic devices with a serial number.

I would like to know how to mark the serial numbers that clients return to me and I have to repair.
I’m not looking to make a return note, just mark that serial number as being under repair to find out
later to get a report and find out how many serial numbers are under repair.
I can do it with tags, but it is very heavy to mark one by one.
Is there a topic that tells me how to manage returns but without making a credit note?

Thank you very much for your time.

Did you figure a solution? I am also looking for a way to handle serialized item repairs that the customer sends back to us and happen on premise.