If there is no court order prohibiting a parent to remove the child out of state without notice to the other parent or to the court, WA laws generally allow both parents equal rights and responsibilities to the child. Among those rights would be the ability to freely travel anywhere lawful with the child.
If by "took our child out of state" you mean that she left the state to live somewhere else, you likely should go to court and ask the court for an order compelling the return of the child to the state. The petition/motion needs to be done before the child is out of state too long.
If you mean that they left the state for a trip and have come back to the state, you likely can ask the court for an order limiting the child's movement. However, unless you have proofs that the child is endangered by the trip or that your time with the child under a parenting plan is compromised by the child's absence from the state, the court likely would not do anything.
If "the divorce process is in progress", you likely should have an attorney to represent and advise you on matters such as this. You should review your specific facts with your attorney.
Sign up to receive a 3-part series of useful information and advice about child custody law.