Said office and official place of business may be changed by passing a resolution to that effect at a previous meeting of the board entered in the minutes thereof and by posting a notice of the same in a conspicuous public place at or near the place of business which is to be changed at least ten days prior thereto, and by the previous posting of a copy of said notice for the same length of time at or near the new location of the office.
RCW 89.30.280