Washington Revised Code Title 34. Administrative Law § 34.05.562. New evidence taken by court or agency

(a) Improper constitution as a decision-making body or grounds for disqualification of those taking the agency action;

(b) Unlawfulness of procedure or of decision-making process; or

(c) Material facts in rule making, brief adjudications, or other proceedings not required to be determined on the agency record.

(a) The agency was required by this chapter or any other provision of law to base its action exclusively on a record of a type reasonably suitable for judicial review, but the agency failed to prepare or preserve an adequate record;

(b) The court finds that (i) new evidence has become available that relates to the validity of the agency action at the time it was taken, that one or more of the parties did not know and was under no duty to discover or could not have reasonably been discovered until after the agency action, and (ii) the interests of justice would be served by remand to the agency;

(c) The agency improperly excluded or omitted evidence from the record; or

(d) A relevant provision of law changed after the agency action and the court determines that the new provision may control the outcome.