Originally Posted by
buckeyefanflyer
Sorry If I was not correct but sometimes you get different answers to quesitons about these type of rules.
If the fare is the same you can do the same day change for $50.00 within 24 hours of your scheduled departure. If the fare is different you can standby but this is airport controlled. Also if the same fare is not avaliable after your scheculed departure you can't standby.
I have 680,000 lifetime miles with CO so I have been on alot of flights and again the rules at times change.
The rules are clear in this case though - it is 24hrs before the new flight, and has been for some time. And to be clear - it's the fare
class that has to be available - not necessarily the same fare. CO will proactively open up fare classes around 24hrs before a flight if there is lots of space, and 3.5hrs before a flight if there is less space (as decided by CO) specifically for the purposes of SDC.