Haw. Rev. Stat. § 431:10-227: Retroactive annulment of liability policies prohibited.

No contract insuring against loss through liability for the bodily injury or death by accident of any individual shall be retroactively annulled by any agreement between the insurer and the insured after the occurrence of such injury or death for which the insured may be liable. The prohibition on retroactive annulment of liability shall also apply to contracts insuring against damage to the property of any person. Any such annulment or attempted annulment shall be void.