Haw. Rev. Stat. § 578-12: Setting aside or modifying decree.

At any time within one year from the date of entry of any decree of adoption, the court may, for good cause, set aside or modify the decree and, in connection therewith, may make appropriate orders, concerning the custody of the minor child and the disposition and handling of the record of adoption by the department of health. The setting aside or modification of any decree of adoption shall not affect any property rights which have become vested between the date of the entry of the decree or the effective date of the decree and the effective date of any order setting aside or modifying the decree of adoption.

No decree of adoption shall be subject to attack in any collateral proceeding, and, after the expiration of one year from the date of its entry, no decree of adoption shall be subject to direct attack upon any ground other than fraud rendering the decree void as of the time of its entry.