If a contract is issued on any basis other than as applied for, an endorsement setting forth such modification(s) must accompany and be attached to the policy; and no endorsement shall be effective unless signed by the policyowner, and a signed copy thereof returned to the insurer.
RCW 48.20.015
Endorsements.
1975 1st ex.s. c 266 s 9.
Official source: Washington State Legislature. Reproduced from public-domain Washington statutes; confirm against the official source for the current text. Not legal advice.