I've used the app to change my Empire train if running late on a connection, but then again I don't usually book on the same ticket because I'm never sure how long I'll want to stop over in NY. And I sometimes don't like what they assign on a single ticket..... for example coming up on the Star in a a couple of weeks, they wanted to make me sit around for two hours and I wanted to see if by some miracle the Star is on time I could make an earlier one. I'm also working in NY the next day, so I have to decide if I'm sending DH alone with the baggage and staying over, or doing the quick 12 hour turnaround going home and coming back in the morning. Still haven't made up my mind