In this case though it's a conflicting view. Let's say 40% of the province don't want to be separated, so they vote to rejoin canada (or form their own thing). Does the now independent Alberta allow it? If not, then why are they allowed to split from Canada? If they do, now this opens up the door for a infinite amount of splits.
Well, it would depend on how the new Alberta is structured. It would be its own country with its own rules. Practically speaking, it would highly depend on whether those 40% are geographically separated from the rest enough to geographically split the new Alberta.