Important context, this referendum isn't binding, but rather a referendum on whether a binding referendum should be held. Separation is deeply unpopular, but Smith has been putting her thumb on the scale every step of the way, and this non-binding referendum isn't subject to the Clarity act in the same way that a subsequent binding one would be.
Is there actually even a legal process for leaving Canada? I would assume you can't just decide to leave. EDIT: oh, there is a process. thats the Clarity Act. This seems extremely surprising - I've never heard of this sort of thing before with any other country.
Does there need to be a legal process? If Albertans are willing to fight a war over it then all they need to do is declare that they don't recognize Ottawa's authority anymore and then go about trying to get other countries to recognize their independence.