Originally Posted by cfischer

if your flight is operated by AA you better ask this question in the AA forum. It really depends on the carrier and when/how such upgrades are processed when on other ticket stocks. Generally speaking, if it is a simple buy-up at check-in ... that very rarely is dependent on the ticket stock ... definitely on board upgrades. Accomplishing this prior to check-in largely depends if this is a surcharge they can bill or whether it is a different booking class and they need to update the ticket