Originally Posted by nd_eric_77
I have noticed that within the past few months, the couple of times I have been put on a carrier which has a code share and/or alliance relationship with the original carrier, the change can be done by e-ticket (most recently, when I was put on a CO flight instead of my original DL one, they were able to do so via e-ticket; I assume this is because they are both SkyTeam & Codeshare partners).
I had the opposite experience a year and a half ago when I tried to switch between a delayed UA flight and a US flight out of DEN. US couldn't get me on their flight until I had gotten my ticket released by UA, then brought the receipt with the ticket number and other pertinent data back to US. I thought that with the Star Alliance their computers would be linked but I guess I was wrong. I was very familiar with the underground train at DEN by the time that episode was over.