How do I stop from inheriting my PU?

I have 2 electors as PUs and it says I have a 18% and 38% chance of inheriting on monarch death, but everytime I roll back the save I always inherit. Is there a way I can stop this from happening. My ruler is currently 82 so options I can do relatively quickly. Is there a way I can turn my PUs into regular vassals? If so I’d rather just do that.