1862(a)(1). (ii) Denial of payment Subject to subparagraph (B)(ii)(II), no payment shall be made under this part for the service unless the Secretary determines pursuant to such process that the service meets the applicable requirements for coverage. (B) Elements of process The process described in subparagraph (A) shall include the following elements: (i) In order to obtain a prior authorization, the provider of services or ambulance service provider shall submit— (I) a valid physician certification statement (PCS) for non-emergency ambulance transport