For an 'F' grade, the course must be repeated within the next three consecutive semesters, but pre-requisite course (if any) should be repeated on priority basis.
As for the improvement of any grade (up to 'B' grade), the incumbent student may be allowed to repeat only one time for a particular course, which should be repeated within next three consecutive semesters.
However, if any student wishes to take this privilege, s/he has to take written permission from the Head of the department and a copy of permission must be sent to the office of the Controller of Examinations within three days from the date of publication of results.
Better grade will be accepted against that particular course for improvement in question, and the previous grade will be marked as 'R' (repeated), and excluded from GPA computation.
For repeat/improvement of a course, a student has to register the course as usually by paying the normal tuition fees (i.e. credit hour basis).