If attendance is set to track for the entire day. Tracking for half a day can be be done by creating a new cycle and applying the cycle to the classes which attendance is not being taken. For example, you may have a class that meets for half a day, every second Tuesday of the month and want to exclude this class from attendance. The other classes which meet on this day can still be included in attendance.
If there is attendance already entered for the days you would like to track for half a day we will need to globally delete attendance.