Originally Posted by
yyznomad
This was a risk I wasn't willing to take to pay a change to an earlier flight not knowing whether I'd be able to even apply eUps. It was positive R still at T-36 but the seatmap stopped showing on EF almost exactly at that point. Would I have been able to successfully eupgrade?
Yes. You can still buy seats after T-36. You just wanted to buy R class.
Seat selection is entirely different. I was not able to select a new seat after that upgrade, but I was able to check in an hour later and select then.