By rights, it should be easier than paper. All participating carriers can see the E-TKT and providing there is no restriction other than the "valid Star carriers" in the endorsement, any of them can exchange and reissue if need be, as that's part of the interline ETKT agreement. Most times, it should be able to done on the phone without venturing into an office. Then again, you're likely to run into the usual Star employee apathy - try anything to get you to go somewhere else for reisse.