Wash. Rev. Code § 26.26B.130
(1) After the period for rescission of an acknowledgment of parentage provided in RCW 26.26A.235 has passed, a parent executing an acknowledgment of parentage of the child named therein may commence a judicial proceeding for:
(3) Before the period for a challenge to the acknowledgment or denial of parentage has elapsed under RCW 26.26A.240, the petitioner must specifically allege under penalty of perjury, to the best of the petitioner's knowledge, that:
[ 2019 c 46 s 3001.]