A community college shall allow a currently enrolled student who is called to active military service to complete any unfinished courses at a later date at no additional charge, unless course credit has already been given or the student received a full refund upon withdrawing from the course (in which case the student’s record shall reflect that the withdrawal is due to active military service). The student must be given priority over other students in reenrolling in the course or courses. The Board may adopt any rules necessary to implement this Section.