Operated and Marketed. Nope.
Cheers.
Nope what?
On more than one occasion, I'd seen people booked on codeshare flights at the airport/AC requested to be added to the upgrade list. AAgents obliged and subsequently bumped me out of number 1 because they were connecting elsewhere
So I know, day of is possible, but in advance?
Maybe I'll book a ticket and see what if I'm able to request an upgrade since AS has the 24 hr cancellation policy.