ATI does not require a waiting period between TEAS attempts. Retake rules are set by the school or program you are applying to, not by ATI.
Before you register to test again, check with your school. Some programs limit the number of attempts per year, some require a set amount of time between attempts, and many have neither — but they may have application deadlines that affect when you should retest. Refer to What do I need to know before I register for the ATI TEAS® exam? for the questions to ask.
TEAS at ATI exams: you may register for another exam date as soon as you like, subject to your school’s policy. Each attempt is recorded on your ATI transcript. If you are retesting, use the Focused Review from your score report to target the topics you missed — see How to improve your TEAS score on a second attempt.