change a organizer to a member

Is the member still a minor? If yes, I apologize but the organizer is the only one that can manage.

try https://support.microsoft.com/en-us/help/12417/microsoft-account-add-members-to-family

Hi, I hope you're doing great out there. I am an Independent advisor and I am here to help you in regard to your concern.

The organizer may need to remove the account first as a member and then re-add as an organizer.

To do so, ask the organizer to sign in to https://account.microsoft.com/family.

I believe there should be at least one organizer so once you add or change an existing account from member to organizer using the current admin account, you should be able to make the changes:

https://support.microsoft.com/en-us/help/12417/microsoft-account-add-members-to-family

The organizer may need to remove the account first as a member and then re-add as an organizer? As the organizer she can not remover herself, I created another organizer who can not remove her organizer account or change it to member?