RCW 26.14.090: Party participation.

(1) A party may:

(a) Be represented in an arbitration by an attorney;

(b) Be accompanied by an individual who will not be called as a witness or act as an advocate; and

(c) Participate in the arbitration to the full extent permitted under the law and procedural rules of this state other than this chapter governing a party's participation in contractual arbitration.

(2) A party or representative of a party may not communicate ex parte with the arbitrator except to the extent allowed in a family law proceeding for communication with a judge.