I wouldn't count on that. It will be a challenge to find a QR agent able and willing to make such changes. Also I don't think QR will make voluntary changes to a ticket issued by AA (or any other airline for that matter).
That's the very reason I said this up-post: "
Not sure if QR has such competent agent as CX. The key is to give them 100% legit flight info on a spreadsheet."