Haw. Rev. Stat. § 88-97: Return to service of a member who has vested benefit status.

If a former member who has a vested benefit status as provided in section88-96(b) returns to service before the former member's retirement, the former member shall again become a member and shall contribute for membership service as provided by the law in effect during the member's reenrolled period of membership. Upon retirement, the member's benefit shall be the benefit computed with the member's combined service included under the formula in effect at the time of retirement.