Yes, was on a conversation-and-hold with Reservations again for another 45 minutes. They claim they can do nothing -- "not allowed to send e-mails from here." I offered to send them an e-mail outlining the circumstances so they could simply reply that this information had reached them and they authorized me to go beyond the 24-hour window, but answer was "No, we can't do that."
Will try again to do it myself in a few hours, but am very reluctant to see myself on the hook for over 2K USD because AA cannot respond and their computer systems cannot "keep up."
Am a bit surprised that AmEx (am a Platinum and have been for 25 years) has not been more supportive. On the other hand, did not try to escalate the situation with them because they have always been reasonable.