The plan so approved by the board of directors shall thereupon be submitted to the known creditors of the district directly affected thereby, in such manner as to the board may seem appropriate and practical under the circumstances. The approval of such plan by creditors shall be in writing filed with the secretary of the board, and such approval shall be irrevocable if approved by a majority in amount of each class of creditors directly affected thereby, within the time specified in such plan.
Idaho Code § 43-2104