You don't.
You as the Organizer would need to leave the Family Sharing group thus removing everyone from it, and Create a new one with your wife's Apple ID. Then add everybody to that Family group.
However:
When you turn off Family Sharing, you leave the family. After you leave a family, you can join or set up a new one. However you can only switch to a different family group once per year.
Leave Family Sharing - Apple Support