Wash. Rev. Code § 35.23.010
Every city of the second class shall be entitled "City of . . . . . ." (naming it), and by such name shall have perpetual succession; may sue and be sued in all courts and in all proceedings; shall have and use a common seal which it may alter at pleasure; may acquire, hold, lease, use and enjoy property of every kind and control and dispose of it for the common benefit; and, upon making a finding that any property acquired for park purposes is not useful for such purposes and that an exchange thereof for other property to be dedicated for park purposes is in the public interest, may, with the consent of the dedicator or donor, his or her heirs, successors or assigns, exchange such property for other property to be dedicated for park purposes and make, execute and deliver proper conveyances to effect the exchange. In any case where owing to death or lapse of time there is neither donor, heir, successor, nor assigns to give consent to the exchange, then this consent may be executed by the grantee. Title to property so conveyed by the city shall vest in the grantee free and clear of any trust in favor of the public arising out of any prior dedication for park purposes.
RCW 35.23.010