Hospital, medical, dental and health service corporations licensed and operating under provisions of this article are hereby authorized to promote and encourage reciprocity with other licensed hospitals, medical, dental and health plans, both within and without the state, in expanding their services to subscribers. In the event that a subscriber to a plan requires emergency hospital, medical, dental or health service, or, in the event that the particular services that he receives are not available through the plan to which he subscribes, such plan is hereby authorized to make payment on behalf of such subscribed for such service on a basis not to exceed its schedule of fees to be paid hospitals, physicians or dentists previously approved by the commissioner and on file in his office.