(1) The arbitral proceedings are terminated by the final award or by an order of the arbitral tribunal in accordance with subsection (2) of this section.

(2) The arbitral tribunal shall issue an order for the termination of the arbitral proceedings when:

(a) The claimant withdraws its claim, unless the respondent objects thereto and the arbitral tribunal recognizes a legitimate interest on the respondent's part in obtaining a final settlement of the dispute;

(b) The parties agree on the termination of the proceedings; or

(c) The arbitral tribunal finds that the continuation of the proceedings has for any other reason become unnecessary or impossible.

(3) The mandate of the arbitral tribunal terminates with the termination of the arbitral proceedings, subject to the provisions of RCW 7.05.440 and 7.05.450(4).