Originally Posted by
emcampbe
On the app (and website), using the check in process, if there are no valid options to change to (or at least, if it doesn't have any that it would present to you), then there will be no change flight button. And IME, it will only ever bring up options in the same fare class - if you want to pay a fare difference to upgrade to a higher fare class, you need to call.
Just a note on this, after you check-in you will get the option of changing your flight on the view reservation page. I am a little confused because sometimes its there and sometimes it isn't. You're post makes sense as to why it wouldn't be there BUT I've had several instances where it was there and there was a fee shown and sometimes a fee plus fare difference. Something triggers it to show up or not but i don't think its based on whether there is a free option or not.