This whole CX/AA relationship is pretty strange although I learned my lesson on how to do it a couple of weeks ago.

Bottomline, once the ticket goes onto AA stock - which it has to - CX deny any association with you and changing anything is a monumental nightmare.

I was booked YVR-HKG-SIN-HKG-YVR

Used 40K to upgrade from J to F and had a great ride out. At time of booking aircraft from SIN-HKG was 2 class but they changed it to 3.

So, without knowing the system, I assumed, no problem, since I'd redeemed the mileage I'd be able to get the UG at the airport. It started going down hill from there. I got no acknowledgement from the counter staff that I had indeed a F ticket (which technically I didn't but in AA's system I did) Under no circumstances were they going to move me up to F.

Ok, so I settle down, get to HKG, enjoy the amenities there and get the bright idea to change from YVR to SFO. SFO was my final destination anyway. Oh my gosh, you'd think CX never had anyone ask to change a flight.

Anyway, after 2 hours, I did get rebooked, even got a refund of some Canadian taxes.

The comes the claiming of my F seat. No chance they say. AA MUST book me into it. Ok, no problem, a quick call back to the EXP desk in the US gets me "waitlisted" on the flight in F. There were 3 open seats but AA couldn't confirm. To cut a long story short, we left with 3 empty F seats and me in J. No huge deal since they seemed to break all the rules in the first place to rebook me but the total lack of respect for a EXP member who has redeemed 40K miles when there is obvious seat availability and I obviously had the "right" to a UG.

Morale to the story: Get your trip signed sealed and delivered (confirmed) by AA before you leave because if you need a UG to clear it probably won't happen.