With an orderly process. Proposals during the offseason only, to take effect at a time in the future, established if not otherwise stated in the new proposal.
Utilizing a quorum of the Gms, allowing for proposals, seconds, discussion and a vote. All done at specific times. So a proposal comes, needs a second in a week, discussion for two weeks, a vote, implemented a year out. Thats an example.
Enough of a small majority changing this league due to appointment, not even by vote of the group. The GMs of this league, in part, have no control over your league.