Originally Posted by
ProfRB
Thanks. I booked the flights on Delta's website, but some of the flights are Korean Air. Should I call Korean to check on availability via Korean for those flights?
You would need to confirm upgrade space with the airline that you purchased the flight from. If you have Delta tickets, even if you are on Korean air for some segments, Delta would need to process the upgrades. Usually the only time a partner airline can process an upgrade on their flight when you are on a DL ticket is at the airport on day of departure.