Try each of the following steps until the issue is resolved:

  1. In Configuration, select Business Rules.
  2. Highlight Scheduling and ensure the checkbox for Reflect class schedule changes is unchecked.
 
  1. In Scheduling, Edit Master Schedule, change from Grid view to List view and manually change the periods.
 
  1. Select Attendance, Enter Class Attendance.
  2. Remove the attendance taken for the course.
  3. Select Scheduling, Edit Master Schedule.
  4. Move the class meeting to the new period.
 
  1. Globally delete attendance. Note: Before doing this, create a Daily Attendance Report. 
  2. Make sure to globally delete attendance twice, once for day and once for class. 
  3. Select Scheduling, Edit Master Schedule.
  4. Move the class meeting to a new period.