1. First capture the current Grade Book Grades and Grades for each student in the current course. This can be done through a Grade Book report.
  2. Remove all grades for this year's students, remove students from the roster, remove sections, and un-offer the course.
  3. Create a new course in Core > School > Department and Courses and give the correct length for the new course.
  4. Offer the new course, create sections, add students, and re-enter the grades obtained from the old course.
  5. Inactivate the old course to avoid confusion in the future.
  6. To do this go to Core > School > Departments & Courses > Edit > mark the course Inactive.