Well, since you're asking, bk-
I vote with JRand56: much cleaner to start your own org. Take those you want from the old group who are willing to join you. Let the old die from attrition. No mess. The only downside would be that those rebel few might be re-energized to fight back, but they might do that anyway. imho.
It was discussed with the head of the theatre department, who felt having two organizations would be too confusing for the LACC foundation, of which the alum association is an adjunct (and therefore get to use their non-profit status, which is very important for fund raising). Had the vote gone differently, I might have.
But, they can't have it both ways - there are bylaws or there aren't and it can't be at their whim - and since they've simply been operating without them for so long (at some point years ago there was a vote to "suspend" the bylaws), the vote was not only for me to take over, but for me to be able to completely restructure the organization the way I want. Hence, I think when that is all figured out, there will be a new set of bylaws. But, for now (and all voters knew this going in), I am the president, and I am about to choose a governing board - the current board members are no longer part of it, but if they want to stay and help they can be part of what we'll call our advisory committee.
I did write the note acknowledging the vote, stated my aims simply, said that I was not an autocrat, and that everyone's input would be welcome, but that in me they've got a leader who's going to make things happen.