Originally Posted by PrivatePilot

I will likely lose my GS status on 1/31/19 but if I book a MILEAGE ticket now for lets say March 2019 and upgrade using a 2020 GPU which is allowed under GS rules and the upgrade clears now and I don't make any changes to the reservation, I assume the upgrade will still stand even though I will only be 1K at the time of the flight? (and 1Ks cant use a GPU on mileage awards). Any insights or experience on this?