I had the Airmiles 7 day ticket in May and tried to upgrade it to an 8 day ticket after using my ticket for 6 days. Guest Relations at Magic Kingdom had a problem with this. I was told they no longer have access to change Canadian tickets. They told me Canadian tickets need to be changed by the company that I got the ticket from prior to leaving Canada??? I have never heard this before.
After the CM asked a manager it was determined the price for the upgrade was over $300. You now have to cover the cost of the extra day plus the discount airmiles paid purchasing the ticket. I would be better off just buying a one day ticket. They ended up giving me the extra day free because I had purchased 5 other 8 day tickets direct from Disney for the rest of my family. I had to fill out paperwork, so I assume this will be on my permanent “Disney record” and they will not do this for me again in the future.