I have actual experience. Perhaps it's something done as a courtesy for high revenue pax.
I've tried three times to get this done. Once via AMEX Centurion travel, once with an excellent TA out of LAX who works for the entertainment industry and once on my own. All three times, shot down. The TA was already cutting his commission for me so that avenue was out. That's about all the TA can do is give up the commission on the sale. We all know how much AA pays out in commissions so don't expect much.