You should at least make sure you have a majority of board members in agreement to cancel a meeting and that ALL of the board members are aware of the decision. They do not have to meet and vote to cancel it, but you don’t want any of the board members upset, claiming they didn’t know or didn’t have the opportunity to object.
Setting or canceling a meeting is a ‘housekeeping’ function. Therefore, any discussion by email or phone is legal. Please make sure the discussion is limited to the cancelation and not on any of the issues which might be on the agenda.
Once you are sure that the board wants to cancel the meeting (not just one member or the superintendent), then you proceed to reverse post it. This means that you notify and post just like you do for a meeting, except this time you are letting everyone know the meeting is canceled.
If you want to be extra careful not to upset people, hang a sign on the meeting room door the day of the meeting stating that the meeting was canceled. That way someone who is unfortunate enough to have seen the original posting but not the cancelation at least will have a chance of figuring out what is going on when they show up for the now canceled meeting.