I would still call day of and try and get concierge to do it for you. I have done it a number of times where my kids were on reward tickets and I was not and I think each time the concierge said they would try and get back to me if there were any problems. When I got to the airport I would check and in each case they would be on the list. Only place I couldn't do it was HNL. No concierge. I may have tried YVR concierge from there since I was connecting through there. That being said, think I was about 50% for upgrades going through since they were on the bottom of the list. That's why I have a number of eup's expiring at the end of the week with all my nominee slots filled up!