Delta Airlines has a prioritized list for passengers to get an upgrade, which is known as the Delta Upgrade List. However, not everyone is eligible to get on this list. To get this list of Delta, one must be a SkyMiles medallion member with Delta Airlines and purchase a fare eligible for upgrade. Complimentary upgrades are prioritized based on status level, fare class, and check-in time. Further, passengers can also make a Delta Airlines Seat Upgrade by paying for an upgrade or by using miles. However, the upgrade on Delta is subject to availability.