42 CFR §411.382

1. (a)
   1. (1)Any advice CMS gives in an advisory opinion does not prejudice its right to reconsider the questions involved in the opinion, and CMS may rescind or revoke the opinion if it determines that there is good cause to rescind or revoke the opinion.
   2. (2)Good cause shall exist where—
      1. (i)There is a material change in the law that affects the conclusions reached in an opinion; or
      2. (ii)A party that has received a negative advisory opinion seeks reconsideration based on new facts or law.
2. (b)CMS provides advance notice to the requestor and to the public of its decision to rescind or revoke the opinion so that the requestor and other parties may discontinue any course of action they have taken in accordance with, or in good faith reliance on, the advisory opinion.
3. (c)CMS does not proceed against the requestor with respect to any action the requestor and the involved parties have taken in good faith reliance upon CMS' advice under this part, provided—
   1. (1)The requestor presented to CMS a full, complete and accurate description of all the relevant facts; and
   2. (2)The parties promptly discontinue the action upon receiving notice that CMS had rescinded or revoked its approval, or discontinue the action within a reasonable “wind down” period, as determined by CMS.