I have a Plat coworker trying to get home early from LAS > CLE within the 24 hour SDC window. All the CO flights direct, or through IAH or EWR are booked solid, but there's a CO flight number on UA metal through DEN, connecting to CO metal DEN > CLE. When she asked the airport agents about going standby on the UA flight, the agents told her she'd have to pay the fare difference. "we can't do that, we're not the same airline yet"