SetSoleOrganizationAdmin

Promotes a member to administrator on organizations that are limited to a single admin. This endpoint is only valid for Team subscriptions (Team Starter and Team Growth) — it returns 400 on any other plan. On these plans, UpdateOrganizationMember cannot promote a member to admin, because doing so would require simultaneously demoting the current admin. This endpoint performs both changes atomically: the caller (who must be the current sole admin) is demoted to member and the target user is promoted to admin.

Note: This endpoint operates on built-in roles only and does not integrate with custom roles.