Robert's Rules of Order are not the final authority at a meeting of an assembly. The constitution or charter of an organization may alter Robert's Rules, as may some kinds of bylaws of the organization. An organization's bylaws will frequently say something like "Robert's Rules of Order will control the conduct of meetings, except that if those Rules conflict with the Charter or the bylaws of the Organization, then the Charter or the bylaws will control."
An agenda is simply indispensable to the conduct of a meeting. Indeed, it is impossible to conduct a meeting of an organization without an agenda. The agenda, once published, cannot be modified without the consent of the members as provided below.
Also indispensable to the conduct of a meeting under Robert's Rules of Order. The minutes should, at a minimum, describe who has raised motions, who has given seconds, who has raised points of order and the outcome of each and every vote. If there has been a division of the house, the minutes should record the actual vote.
The success or failure of a meeting conducted under Robert's Rules of Order frequently
depends upon the judgment of the Chair. Knowledge of the rules is helpful, but not
indispensable: common sense and good judgment are far more useful than a detailed
knowledge of the Rules.