Haw. Rev. Stat. § 11-19
Whenever a registered voter changes residence from one county to another, the person shall notify the clerk and change the registration to the proper county by the appropriate registration deadline; provided that no change of registration shall be allowed after the close of registration for an election except pursuant to section 11-21(c). Thereupon, if the person applying is legally qualified to register, the clerk shall accept the registration and shall immediately thereafter forward to the clerk of the county in which the person was formerly registered, a notice that the name of the registered voter is to be removed from the general county register of that county.
HRS § 11-19
Attorney General Opinions
Except in the situation specified in section, voter who moves from one county to another may reregister in second county, so long as register is open. Att. Gen. Op. 70-16.