Funnily enough, I have a ticket for which the itinerary says: "Prior to day of departure - No ticket changes are permitted."

However when looking at the rules in detail, they say: "CHANGES: BEFORE DEPARTURE CHARGE CAD 300.00 FOR REISSUE/REVALIDATION. ."

Now, I don't need to change it, and I cannot see that I could possibly get a better price for that trip. But one wonders..