It could be risky trying to use coupons out of sequence. VIA operates an "all reserved" system; many trains have specifically assigned seats in comfort class (coach), although most don't, and all first class seats and sleeper rooms/berths are specifically assigned in advance. Most Service Managers (new term for conductors) do look closely at tickets, in my experience.

I have been told by ticket agents that although tickets expire after one year, the amount of money paid for the fare can remain as a credit. In other words, although you can't use an expired ticket - by changing the reservation - it can be exchanged as a voucher for payment or part payment of another ticket. I have no experience of doing this myself, though. If a ticket has been partly used, the remainder of its value, less any cancellation fees, can be calculated to determine its net value. There are no cancellation fees on full coach fares (Liberty), VIA 1 first class corridor tickets, and full-fare sleeper tickets. Most coach cancellation fees are only $15 plus, as airlines say, any fare difference.

For some reason a few years ago VIA told agents they cannot use those orange stickers. I recently had to have a ticket reprinted even though the only change made was to an assigned seat number on the same date and train. An exception to that rule can be made only if the computer is being difficult.