Updates a phone menu. A partial body is safe: your fields are merged over the current menu, so anything you omit is preserved. options is the exception — sending the array deletes and recreates every key press, so omit the key to keep the stored ones. The updated menu is not returned, so re-read it with GET /api/v1/ivr_menus/{menuId}; and a menu owned by a call flow answers 409 before anything is written. Identity fields are not settable here: the record's own id, its account, and its call-routing id are always taken from the stored record, and sending them has no effect.