Originally Posted by
astroflyer
You should not get SDC for free unless you have UA gold status. You may occasionally get lucky with an agent on the phone or at the airport, but don't plan on it.
I can see the rationale for not giving a generous 24 hour SDC out to everyone. I do think they should loosen up the standby policy at the airport. If nothing else it can take some pressure off later flights.
I believe this is correct, often agents will do a change simply to be helpful or to take pressure off later flights, at the end of the day if there are empty seats to be had there's no sensible reason not to fill them.
I regularly "SDC" on US despite having no status with them directly (UA 1K), usually I have to ask a couple of different people to get the right answer though.