Originally Posted by
mildfrequence
If I SDC from a flight previously GGU'd, in order to preserve the upgrade is U space required on the new flight, or would they give me any open spot in the cabin? And if there is no availability one way or the other, will they return the GGU to me?
Im not 100% sure but last year when I tried this U space was required OR they just put me on the regular upgrade list which if you are doing SDC it is likely F is already full (unless they are waiting for very last minute gate upgrading). If you change a flight like SDC or any other change you can contact customer care and get replacement GGU.