Wash. Rev. Code § 32.24.030
An unconverted mutual savings bank may for the purpose of consolidation, acquisition, pooling of assets, merger, or voluntary liquidation arrange for its assets and liabilities to become assets and liabilities of another mutual savings bank, by the affirmative vote or with the written consent of two-thirds of the whole number of its trustees, but only with the written consent of the director and upon such terms and conditions as he or she may prescribe.
Upon any such transfer being made, or upon the liquidation of any such mutual savings bank for any cause whatever, or upon its being no longer engaged in the business of a mutual savings bank, the director shall terminate its certificate of authority, which shall not thereafter be revived or renewed. When the certificate of authority of any such corporation has been revoked, it shall forthwith collect and distribute its remaining assets, and when that is done, the director shall certify the fact to the secretary of state, whereupon the corporation shall cease to exist and the secretary of state shall note the fact upon his or her records.
In case of the consolidation with or voluntary liquidation of a mutual savings bank by another mutual savings bank, as herein provided, any sums advanced by its incorporators, or others, to create or maintain its guaranty fund or its expense fund shall not be liabilities of such mutual savings bank unless the mutual savings bank, so assuming its liabilities shall specifically undertake to pay the same, or a stated portion thereof.
RCW 32.24.030