Thank you BCL. I see how to change the ticket on my phone app, where the tickets are shown. That looks easy enough, I'll just keep the one set of tix for the 2:10 and change via app if we manage to get there early. The station info on the Amtrak site says we should arrive 30 min prior departure. If we don't get there until, say, 15 min before departure, would I still be allowed to request a change to my ticket? How far in advance do you really have to arrive for a train?
Yes the_traveler, the departure times are 1:10 and 2:10, on a Saturday. Maybe there different trains on weekdays?
I wouldn't rely on it, but I have seen conductors who have allowed passengers to board a train without a valid ticket, as long as the passenger would buy a ticket on board using an electronic device. This was at a station with Quik-Trak, and the passenger could have bought a ticket from the conductor with a penalty, but buying it from the Amtrak website saved the surcharge. It might be possible to board the train then modify it if tickets are available. I don't know how possible it is to do on a reserved train though. I've seen it done on Capitol Corridor, although generally a ticket on that route can always be used on an earlier or later train by definition. I don't have a whole lot of experience modifying a ticket given the route I use, although I have done it a few times well ahead of the train.
You should have the option of modifying your reserved coach ticket until such time that you're declared a no-show. The issue I would see with modifying to an earlier train is whether or not the tickets are sold out or past a point where they're no longer available. I've checked before out of curiosity, and sometimes tickets are still listed as available even after the train has left the station.