***NOTE: Please visit AWS's FAQ for the latest policy on retaking exams***
Test takers who do not pass an exam must wait 14 days before they are eligible to retake the exam. There is no limit on exam attempts until the test taker has passed. For each exam attempt, the full registration price must be paid. Beta exam test takers are eligible for one attempt only.
Please see our How do I schedule an AWS certification exam? for a comprehensive step by step process on scheduling the exam.
Good luck and Happy learning!