Originally Posted by JerryFF
If you have an "airport-specific" fare, such as often the case for IAD-OAK, you are theoretically not allowed to standby for DCA-OAK, even though DCA and IAD are coterminals for routing purposes. However, airport agents will often let you do it. But it is at their discretion and not part of the regular fare rules.
If you actually have an airport specific fare, the computer now makes it very hard for an agent to get you on another flight. I tried this with LAX and SNA last year and the RCC agent could not get the computer to accept me onto the SNA flight.