family sharing

About Family Sharing

1. Set up Family Sharing
2. Family Sharing - Apple Support
3. Share purchased content with Family Sharing
4. Family Sharing and Apple IDs for kids
5. Share an iCloud storage plan with your family - Apple Support
6. Leave Family Sharing
7. iCloud - Family Sharing - Apple Support
8. Family Sharing and Apple IDs for kids

You need to disband the existing family using the steps in the articles Kappy posted. The new organizer can then set up the new family and invite the family members to join the new family. If there are children under 13 years old, the new organizer needs to leave the existing family, set up the new family, and then the under 13 years old children can be transferred to the new family. Then disband the old family and join the new family.