Wash. Rev. Code § 3.20.100
Change of venue—Affidavit of prejudice
If, previous to the commencement of any trial before a justice of the peace, the defendant, his or her attorney or agent, shall make and file with the justice an affidavit that the deponent believes that the defendant cannot have an impartial trial before such justice, it shall be the duty of the justice to forthwith t…