Wash. Rev. Code § 35A.09.040
Within ten days after the results of the election authorized by RCW 35A.09.030 have been determined, if a majority of the votes cast favor the proposition, the members of the charter commission elected thereat shall convene and prepare a new or revised charter by altering, revising, adding to, or repealing the existing charter including all amendments thereto and within one hundred and eighty days thereafter file it with the county auditor. The charter commission shall be organized, vacancies filled, alternative plans of government considered, and a public hearing held all in the manner provided in sections of chapter 35A.08 RCW relating to charter commissions, and the commission members shall be reimbursed for their expenses and may obtain technical and clerical assistance in the manner provided in chapter 35A.08 RCW. Upon the filing of the proposed new, altered, changed, or revised charter with the county auditor, it shall be submitted to the registered voters of the charter code city at an election conducted as provided in RCW 35A.09.060.
RCW 35A.09.040