Haw. Rev. Stat. § 88-61: Termination of membership.

(a) Except as otherwise provided by section 88-96, any member absent from service for four calendar years following the calendar year in which the member's employment terminated shall cease to be a member, and the former member's credited service shall be forfeited.

(b) Any member who withdraws the member's contributions, becomes a retirant, or dies, ceases to be a member as of the date of withdrawal, retirement, or death.