If the trustees of any solvent mutual savings bank deem it necessary or expedient to close the business of such bank, they may, by affirmative vote of not less than two-thirds of the whole number of trustees, at a meeting called for that purpose, of which one month’s notice has been given, either personally or by mailing such notice to the post office address of each trustee, declare by resolution their determination to close such business and pay the moneys due depositors and creditors and to surrender the corporate franchise. Subject to the approval and under the direction of the director, such savings bank may adopt any lawful plan for closing up its affairs, as nearly as may be in accordance with the original plan and objects.