How to upgrade delta international flight? Passengers, Delta upgrades internationally. To upgrade to an international flight, one can submit their request through the "Upgrade Certificate Request," "My Trip," or "Automatic Upgrade for any Medallion members." if you could upgrade to an international flight, then it may be expensive. https://www.airlinesgrouptravel.com/blog/how-to-upgrade-on-delta #DeltaUpgrade #InternationalFlights #DeltaBusinessClass