Wash. Rev. Code § 35A.36.060
In order to designate a proxy to affix his or her signature to bonds, a code city officer shall address a written notice to the legislative body of the city giving the name of the person whom he or she has selected therefor and stating generally or specifically what bonds are to be so signed.
Attached to or included in the notice shall be a written signature of the officer making the designation executed by the proposed proxy followed by the word "by" and his or her own signature; or, if the notice so states, the specimen signatures may consist of a facsimile reproduction of the officer's signature impressed by some mechanical process followed by the word "by" and the proxy's own signature.
If the authority is intended to include the signature upon bonds bearing an earlier date than the effective date of the notice, the prior dated bonds must be specifically described by reasonable reference thereto.
The notice designating a proxy shall be filed with the city finance officer or city clerk, together with the specimen signatures attached thereto and a record of the filing shall be made in the journal of the legislative body. This record shall note the date and hour of filing and may be made by the official who keeps the journal at any time after the filing of the notice, even during a period of recess or adjournment of the legislative body. The notice shall be effective from the time of its recording.
RCW 35A.36.060