Originally Posted by
sbm12
You only need to be within 12 hours of the new departure time to make your request, so long as the new flight is within 24 hours of your original departure time. So from that perspective the answer to #2 is a resounding yes.
As for #1, I believe that the rule is that the specific fare class must be available; that is what the rule was prior to this change and I do not think they changed that aspect of it. Normally CO will open up all the revenue fare buckets to facilitate such a change. I have no idea how it plays out with a reward reservation.
The issue here is that there is a difference between requesting a change under the new system and going standby. Standby is only permitted same-day regardless of fare class whereas the new policy is as long as the flight is within 24 hours of the original. So if, they'll let me go standby even though it's 10 minutes before midnight I should be OK. However, if they don't then I'm subject to the new change policy which seems to require the same fare class be available.