Section 26.26A.450 - Adjudicating parentage of child with adjudicated parent(1) If a child has an adjudicated parent, a proceeding to challenge the adjudication, brought by an individual who was a party to the adjudication or received notice under RCW 26.26A.410, is governed by the rules governing a collateral attack on a judgment.(2) If a child has an adjudicated parent, the following rules apply to a proceeding to challenge the adjudication of parentage brought by an individual, other than the child, who has standing under RCW 26.26A.405 and was not a party to the adjudication and did not receive notice under RCW 26.26A.410: (a) The individual must commence the proceeding not later than four years after the effective date of the adjudication.(b) The court may permit the proceeding only if the court finds permitting the proceeding is in the best interest of the child.(c) If the court permits the proceeding, the court shall adjudicate parentage under RCW 26.26A.460.Added by 2018 c 6,§ 511, eff. 1/1/2019.