Legal Question in Family Law in Washington

For purposes of this question and my response, I will assume that you you are separated and in dissolution proceedings. If so, make a motion to the Court asking for this specific vacation you'd like to take. Later, when you are ready to finalize the divorce or if it goes to trial, make sure you ask that either parent be allowed to take the children out of state on vacations, with notice to the other parent, or at least make sure that there are no restrictions on either of your rights to do so within the Parenting Plan that is ultimately entered.

Ultimately, as with all persons who try this, I suggest you hire local counsel to help you. Best of luck.