Question: What does CMS's policy on revalidation of provider enrollment information imply? South Carolina Subscriber Answer: Under this policy, providers and suppliers who enrolled in Medicare before Mar. 25, 2011 must revalidate their enrollment information between now and Mar. 23, 2013. The Center for Medicare and Medicaid Services (CMS) specifically states that this must be done only after receiving notification from their Medicare administrative contractor (MAC) (see CMS SE1126 at http://www.cms.gov/MLNMattersArticles/downloads/SE1126.pdf.) Wait for notices sent out by your MACs to begin your revalidation process.