That would require the assent of every province due to the ay our constitution is structured, and every indigenous tribe with a treaty signed by the Crown because one party to a treaty can't unilaterally alter the terms like that. That would make it every bit the shitshow that totally removing the Crown would be.

The only way something like this could happen would be if the monarchy tried to pull some bullshit like they did in Australia. That would cause a constitutional crisis of epic proportions and create the political will to remove them entirely. I don't think it's a realistic thing, though. The monarchy know damned well that we're only content to leave this can of worms unopened because they don't interfere with us.