You must pay the full exam fee each time you take the exam.
Exam Retake Rule:
You must wait at least 3 calendar days after your first attempt to take the exam again. Third attempts must wait at least 14 calendar days after the second attempt.
Each exam may be taken for a total of 3 times in a 12 month period. The 12 month period starts from the date the first exam is taken. For example, if the first exam is taken on May 1, 2014, a candidate may take the same exam 2 more times before May 1, 2015.
You must pay the full exam fee each time you take the exam.