Yes. Don’t get thrown off by the word “final.” Washington allows for a final parenting plan to be modified. Modification may be done either through agreement or by court order. A court requires for most modifications that you demonstrate a significant change in circumstances in the other parent’s home that were not contemplated at the time the original parenting plan was issued. It is best to talk to a child custody attorney ***link*** to determine whether or not you have a proper legal basis to modify an existing parenting plan.
Often parenting plans require the parties to go through dispute resolution prior to going into court to modify an existing parenting plan. Each parenting plan is different, but commonly dispute resolution involves an uninvolved third party hearing from both sides and trying to reach a settlement of the matter without resorting to the court.