I first really understood how complimentary upgrades work on Delta after a business trip where I booked a simple Main Cabin ticket and didn’t expect anything extra. A day before departure, I noticed I was on the upgrade list thanks to my Medallion status, and a few hours before boarding, I cleared into Comfort+. It felt like a nice bonus. On another trip, I changed flights last minute and worried it would mess up my upgrade chances. Calling 8 8 8-2 1 7-3 3 2 4 made it easy—they helped me modify the booking and explained how complimentary upgrades would still apply.
