An Approved Candidate has met the NCCAOM eligibility requirements and will be authorized to sit for the NCCAOM exams. The NCCAOM® Authorization to Test (ATT) Letter is mailed to the applicant via the U.S. Postal Service. Therefore, it is imperative that the candidate keep their physical address up-to-date with the NCCAOM. The ATT letter is very important because it contains the information needed to schedule examinations and gain access to the Pearson VUE testing center. The candidate has the flexibility to select their own schedule and can register by telephone or over the internet.