Thanks for the advice everyone...I had been planning on just using my already-printed ticket for another trip on the same train in October. That would've turned out terribly! And that reminds me of a fairly stupid question I've always wondered - do conductors actually kick people off trains? Aside from the very rare instances where people who simply don't have tickets board the train, I've never seen it happen. Do you think it would've happened if I tried to board a train for a date after the date printed on my ticket?

Also, another question - what happens if the price of the ticket I exchange my current one for is lower? Do I get a refund of the difference?

Sorry for the rant and barrage of questions - I'm new to the FlyerTalk community.