As Medicare tightens up its enrollment procedures, it also is issuing official instructions on how to rebut a deactivation of Medicare billing privileges. Change Request 10978, issued Sept. 30, “provides instructions for MACs to advise providers/suppliers of their rebuttal rights, as well as for receiving and processing rebuttals,” the Centers for Medicare & Medicaid Services says in an accompanying MLN Matters article. For example: MACs must receive the rebuttal submission within 20 calendar days from the date of the deactivation letter, CMS says in the CR at www.cms.gov/Regulations-and-Guidance/Guidance/Transmittals/2019Downloads/R904PI.pdf.