Wash. Rev. Code § 19.110.090
Every person who proposes to sell or lease a business opportunity in this state through any person acting on an agency basis in the common law sense shall file with the director, in such form as the director by rule prescribes, an irrevocable consent appointing the director or the director's successor in office to be the attorney of the applicant to receive service of any lawful process in any noncriminal suit, action, or proceeding against the applicant or the applicant's successor, executor, or administrator which arises under this chapter or any rule or order hereunder after the consent has been filed, with the same force and validity as if served personally on the person filing the consent. A person who has filed a consent in connection with a previous registration need not file another. Service may be made by leaving a copy of the process in the office of the director, but it is not effective unless (1) the plaintiff, who may be the director in a suit, action, or proceeding instituted by him or her, forthwith sends notice of the service and a copy of the process by registered mail to the defendant or respondent at the last address of the respondent or defendant on file with the director, and (2) the plaintiff's affidavit of compliance with this section is filed in the case on or before the return day of the process, if any, or within such further time as the court allows.
RCW 19.110.090