I purchased a relatively high fare bucket ticket a few days out from travel for journey NAS-YYC on AA connecting in CLT and DFW, flights were pretty full and the schedule wasn't ideal so I booked a ticket with flexibility in case anything else opened up. The day before and within 24 hours of travel seats opened up on the earlier 11am flight to CLT via DFW getting back same day rather than the original ticket with a 7 hour forced overnight in DFW.

The booking however was not able to be modified once purchased - there were no changes online at all / zero self serve options - just a message to contact Reservations for changes. Because the ticket was billed to a Canadian credit card address, the fare was in CAD, and that automatically disqualifies you from getting any assistance via the in-app chat as they can only assist with USD fares.

I phoned into Reservations twice, the first agent said he couldn't make the changes to a CAD ticket but would have someone call me back, I did get a callback but no one was there when I answered. The final attempt with reservations I was told that it's not possible to make any changes to the tickets once within 24 hours by phone, only online. She transferred me to a web / IT helpdesk, and they then transferred me back to someone that couldn't assist with tickets in CAD.

My attempts to use SDC on American with a CAD issued ticket were an exercise of extreme frustration and I ended up buying a new ticket on DL via ATL instead.

Long and short - if you are an international traveller using a non-US billing address and fare currency - don't expect to avail of SDC on American.