42 C.F.R. § 438.102
(a) General rules.
(1) An MCO, PIHP, or PAHP may not prohibit, or otherwise restrict, a provider acting within the lawful scope of practice, from advising or advocating on behalf of an enrollee who is his or her patient, for the following:
(b) Information requirements: MCO, PIHP, and PAHP responsibility.
(1)
(i) An MCO, PIHP, or PAHP that elects the option provided in paragraph (a)(2) of this section must furnish information about the services it does not cover as follows:
(A) To the State—
(1) With its application for a Medicaid contract.
(2) Whenever it adopts the policy during the term of the contract.