The UMBAA ByLaws can only be amended at a meeting of the general membership by a two-thirds vote of the members in good standing present.

In 2007 the Bylaws were amended to allow the board to keep a list of "Standing rules" that can be changed by a vote of the UMBAA Board.  Standing Rules are related to the details of administration of the organization.

A pdf of the Bylaws (version 8/21/2008) can be found here.

A pdf of the standing rules can be found here.