You create a calculated exception to schedule a recurring event that takes precedence over a scheduled weekly event.
In WorkStation, in the System Tree pane, select the schedule you want to add the calculated exception event to.
Click the Basic tab.
On the Basic toolbar, click the New schedule event button
In the Schedule Event Properties dialog box, under Event type , click Exception .
Under Exception type , click Calculated .
Select All Day to have the event last all day.
In the Name box, type a name for the exception.
In the Priority box, enter a priority.
In the Month box, select a month.
In the Week of month box, select a week of the month.
In the Day of week box, select a day of the week.
Click OK .