§ 3019-a. Notice of termination of service by teachers. A teacher who desires to terminate his services to a school district at any time, shall file a written notice thereof with the school authorities of such school district or with the board of cooperative educational services or county vocational education and extension board at least thirty days prior to the date of such termination of services. School authorities or such boards which desire to terminate the services of a teacher during the probationary period shall give a written notice thereof to such teacher at least thirty days prior to the effective date of such termination of services.