set autocommit=0;
USE provisioning;

ALTER TABLE provisioning.rtc_session
    DROP FOREIGN KEY tl_subscriber_ref,
    DROP KEY subscriber_idx;

ALTER TABLE provisioning.rtc_session
    ADD KEY subscriber_idx (subscriber_id),
    ADD CONSTRAINT tl_subscriber_ref FOREIGN KEY subscriber_idx (subscriber_id)
        REFERENCES voip_subscribers (id) ON DELETE CASCADE ON UPDATE CASCADE;

commit;