It would require an act of Parliament. As Harry continues to step in it…I imagine there would be enough folks willing to kick him to the curb.
If nothing else, Charles can say the family will no longer consider him worthy of the title…and Parliament can do what they will.
We never know for sure the truth of what is circulated on the Internet, but I’ve seen one story indicating that some in Parliament did want to present a bill, may have already done; and Charles rejected the idea.
Who knows what can happen in the future...this couple seems bent on destruction.