Originally Posted by
squirk
Fare class was (is) N, as it was a Main Economy booking with miles. I was upgraded to C+ by virtue of my Plat status. I guess I’m out of luck then, yes?
Correct, there is no way to apply a Mileage Upgrade Award to an award flight. They are only applicable to revenue fares. You can also now apply them to Premium Select fares (P/A/G fare classes) which I believe are 40K on TATL routes. G fares can often be cheaper than K coach fares.
Delta Mileage Upgrade Awards