Oregon Revised Statutes Remedies and Special Actions and Proceedings § 36.498

(1) Within the period of time agreed upon by the parties or determined by the arbitral tribunal, the claimant shall state the facts supporting the claim of the claimant, the points at issue, and the relief or remedy sought, and the respondent shall state the defense of the respondent in respect of these particulars, unless the parties have otherwise agreed as to the required elements of those statements.

(2) The parties may submit with their statements all documents they consider to be relevant or may add a reference to the documents or other evidence they will submit.

(3) Unless otherwise agreed by the parties, either party may amend or supplement the claim or defense of the party during the course of the arbitral proceedings, unless the arbitral tribunal considers it inappropriate to allow the amendment or supplement having regard to the delay in making it.