Maybe
you should pay more attention when reading. On the page I mentioned before, it clearly states:
OCP Exam Vouchers with a free retake included (i) can be used by one person on one attempt plus a retake of the same exam (ii) can only be used for a retake if there is a failed first attempt on file, (iii) becomes void for both attempts on the voucher expiration date.
So if you don't have an exam voucher with free retake included, you'll have to purchase another one if you need to retake the exam