RCW 35A.10.020

Any charter code city, which has been so classified under the provisions of this title for more than six years may abandon such classification and elect to be governed according to its charter under the general law relating to charter cities of the classification held by such city immediately prior to becoming a charter code city, if any, or may elect to be governed by the general law relating to charter cities of the highest class, or other class, for which it is qualified by population.