want to change the organizer email is no longer valid
How do I delete myself as the family organizer for family sharing? The email used for this is no longer valid.
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You don't need to delete yourself as organizer unless you want to. You can do a name change on your current Apple ID and remain the organizer. Note the restrictions in the article.
What to do after you change your Apple ID or password - Apple Support I suggest doing this before you change your Apple ID or password.
If you want to change the organizer, you need to disband the family.