(1) If the period of employment agreed upon between the parties exceeds three years, or if it is to continue for the lifetime of one of the parties or of a third person, either party may give notice of his intention to rescind the contract of employment for the future at any time after the expiration of three years.
(2) In the case of paragraph (1), the notice of intention to rescind the contract of employment for the future by either of the parties becomes effective after three months have elapsed from the date of receipt by the other party of such notice.