My interpretation of the OP's scenario is this: "I bought a ticket last October, I want to cancel today, and I'm hoping to avoid a cancellation fee if by any chance there was a schedule change between last October and today."

In this scenario, if you're planning to cancel your ticket online, then before you get to see your booking details you will be presented with a screen in which the schedule change is explained. You will need to accept the change before you can do anything else with the booking. If you don't accept the change, you can then call and cancel the booking. If you do accept the change, you're toast.

I don't know what happens when you cancel by phone without going online first. I don't know if the phone agent will proactively tell you there was a schedule change before you say you want to cancel.