42 CFR §422.113(c)(2)

(iii) Is financially responsible for post-stabilization care services obtained within or outside the MA organization that are not pre-approved by a plan provider or other MA organization representative, but administered to maintain, improve, or resolve the enrollee’s stabilized condition if –

a. The MA organization does not respond to a request for pre-approval within (1) hour

b. The MA organization cannot be contacted

c. The MA organization representative and the treating physician cannot reach an agreement concerning the enrollee’s care and a plan physician is not available for consultation. In this situation, the MA organization must give the treating physician the opportunity to consult with a plan physician and the treating physician may continue with care of the patient until a plan physician is reached or one of the criteria in §422.113(c)(3) is met. (Emphasis added.)