Sudden date changes of Regular Meetings

In December, my local School Board set the dates for the next twelve months of Regular Meetings.  This new schedule was added to the online calendar of the school's website.  January's meeting was canceled due to adverse weather conditions.  February's meeting had been scheduled for Wednesday, the 17th.  Now, looking at the Agenda posted today, I see that is says the meeting is to take place on Thursday, the 18th. 

Now, with only a few days warning to rearrange my schedule so that I can attend the meeting (and I only have this much time because of my vigilance), I am left wondering...Can they make last minute alterations to set Board Meeting Dates, and if so, what legal obligations do they have in regards to properly notifying the public?  Is putting the new date on the posted Agenda enough?

On the other hand, I am also wondering..If the date change is a typo, can the meeting take place at the previously scheduled date or must they abide by the date printed on the posted Agenda?

I would greatly appreciate any response to my questions.  I need to know my rights before the next meeting, otherwise I'm sure they will just do as they please and the community will again be left out in the cold:o(

In my opinion, 72 hour notice is actually insufficient for regularly scheduled meeting agenda items.  Twenty four hour notice is definitely insufficient for the public, particularly because important issues can be discussed at meetings that are considered "special," only by virtue of the fact that they are not regularly scheduled on the calendar.  This creates a "catch all" for our city, Encinitas, for example, to label every single closed session a "stand alone special meeting," solely for the purpose of giving the public less notice, only 24 hours.  The Brown Act does discuss closed sessions under Regular Council Meetings, so presumably, if legal counsel and the City Manager are aware of a case to be discussed in advance,  the closed session could and should be a part of the regularly scheduled meeting so that interested parties could have at least 72 hour notice.  Public participation should be encouraged, not discouraged.