Any member of a Neighborhood can leave it by tapping Quit in the Neighborhood information window.
If you are the only player in the Neighborhood, it will be deleted.
If you are the leader of the Neighborhood and there are other members, you first have to promote another player to leader. Otherwise, you cannot quit the Neighborhood.
If you change several Neighborhoods in one day, you will have to wait a certain period of time before joining another Neighborhood.