425. The beneficiary in whose favour insurance contemplated by the Husbands and Parents Life Insurance Act (Revised Statutes, 1964, chapter 296) has been effected becomes a beneficiary irrevocably designated according to the prescriptions of this Act.
However, the policyholder or participant may, within twelve months after 20 October 1976, only once change the designation in accordance with sections 12 and 13 of the said Husbands and Parents Life Insurance Act. The designation arising from the change provided for in this paragraph is irrevocable.