RCW 2.04.150: Apportionment of business—En banc hearings.

The chief justice shall from time to time apportion the business to the departments, and may, in his or her discretion, before a decision is pronounced, order any cause pending before the court to be heard and determined by the court en banc. When a cause has been allotted to one of the departments and a decision pronounced therein, the chief justice, together with any two associate judges, may order such cause to be heard and decided by the court en banc. Any four judges may, either before or after decision by a department, order a cause to be heard en banc.