Haw. Rev. Stat. § 88-340: Termination of membership.

Except as otherwise provided by section 88-341, any class H 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. Any class H member who withdraws the member's contributions, becomes a retirant, or dies, shall cease to be a member as of the date of withdrawal, retirement, or death.