Originally Posted by maskedmesothorium

I think the quick answer is that it's going to be up to the discretion of the individual employee. In the past, when I called in, the agents never knew it was free for elites and they would have to escalate to a supervisor to confirm. When I've SDC'd in-person, it's been 50/50. I have successfully changed to a flight a full 24 hours before my scheduled flight, but I was surprised they allowed it. It's not a big deal if you're already checked-in, but they will have to undo it if you SDC.