Quick question: Yesterday I bought an international ticket and received the E-ticket confirmation email as expected with ticket number etc. At some point I called to request cash and miles upgrades (probably before I had actually received the E-ticket, but after having paid). An hour later I received another E-ticket (same itinerary and seats, so no upgrade yet) with a new ticket number and the notation "Exchange" in the receipt area. Any idea what this means?
[Edited to add) It appears the class of flight was Q on all segments and is now N.
Thanks