I'd make sure and check your reservation: I have a mixed CO / UA reservation with a UA upgrade with copay. I'd been upgraded at ticketing. Called them today after noticing a wonky itin, according to the CO Elite desk, quoting the UA Elite desk, a "software glitch" associated with the fact that I hadn't paid yet for my UA metal upgrade had downgraded me to the waiting list and moved my return flight to the same day as my outbound. Took an hour for the desks to figure out.