Please see this link for the withdrawing refund schedule. Withdrawing means student has dropped to zero hours.

When taking more than one course and student drops a course between the 1st and 5th day of class (4th day of class for summer semester) leaving student still enrolled in one or more courses, student will receive 100% refund. After the 5th day of class (4th for summer), if student does the same, the student will not receive any refund.