Corporations not for profit, of this class, heretofore organized under the general incorporation laws, or laws later enacted, are empowered to combine into associations upon such terms as may be provided and agreed upon, or by one becoming a member of the other. Further, preexisting charters of such corporations are hereby amended, under the power reserved to the general assembly, so as to bring such corporations into conformity with this chapter, thus granting such corporations the powers and imposing upon them the duties and liabilities set forth in this chapter.