Set member role

Sets a member's role. A member holds exactly one role per organization. role_ids must contain exactly one id and REPLACES whatever they held; zero or two or more answers 400 role_cardinality. To combine two roles' permissions, author a custom role (POST /role) — a second assignment would create a privilege level no role names. Takes effect on the member's next request. Requires member:manage, and you may only assign a role whose permissions you hold yourself, so a member admin cannot promote anyone (including themselves) past their own level. A browser session must also pass a fresh step-up reauthentication in the app (without it the call answers 428 step_up_required). An organization API token is not challenged.