Ugh leaving Tues and still don’t know what to do. Ask to have them upgrade my Canadian Voucher to AP and take the chance they won’t or just buy an AP.
I think you'll be able to upgrade your Cdn Resident tickets. I know that Days In the Sun had some trouble with this recently, but that's the only report I've seen. Many, many people have upgraded these tickets without issue, and even in that recent case there was a different answer given the very next day. In the off chance that you do run into trouble, I'd just try somewhere else.
That said, the bigger question is whether it is advantageous for you to upgrade the Canadian Resident ticket. Unless you are very lucky, you *will* lose the discount on the upgrade. If you know you will use the ticket sometime in the future, and you don't mind having the $$ tied up in the meantime, your best bet for an AP upgrade is to buy a heavily discounted ticket from some place like
Undercover Tourist. Those tickets are discounted by the retailer, not by Disney, so they will be price-bridged on an upgrade, and you will save the discount. Then you can use your cheap(er) Canadian Resident ticket some other time.
eg. Today you can buy an adult 5-day park hopper from Undercover Tourist for $427.95. That ticket should be worth $473.93 on upgrade, so you save $46. It's not huge on an AP that costs several hundred dollars, but it's the best deal going for APs.
Of course if you got your Canadian Resident ticket "free" from Air Miles and just want to cash it in for whatever its worth, that's a pretty good deal too!