Originally Posted by
number_6
True in the past 20 years; but starting in 2007 it has become increasingly difficult (even with non-OWE tickets). The whole endorsement process (which is needed without a reissue) has become more convoluted (or rather has moved from the back office which the airline took care of days after you flew, to the front office which you must take care of at the airport before you board). How much help you get seems to depend on how busy the airline is that day (so it can become a reissue).
I flew on a AONE3 segment two weeks ago where I changed the carrier after initial ticket issue, and did so without a reissue. The other OW carrier lifted the electronic segment from the ticket just fine.