42 C.F.R. § 435.212
Individuals who would be ineligible if they were not enrolled in an MCO or PCCM
The State agency may provide that a beneficiary who is enrolled in an MCO or PCCM and who becomes ineligible for Medicaid is considered to continue to be eligible—
(a) For a period specified by the agency, ending no later than 6 months from the date of enrollment; and
(b) Except for family planning services (which the beneficiary may obtain from any qualified provider) only for services furnished to him or her as an MCO enrollee.