42 C.F.R. § 512.260 – Billing.

(a) Reassignment of billing rights. Each Professional participant and Dual participant must ensure that its individual practitioners reassign their billing rights to the TIN of the Professional participant or Dual participant.
(b) Billing under the RO Model.
1. (1) Professional participants and Dual participants must bill an RO Model-specific HCPCS code and a SOE modifier to indicate that the treatment planning service has been furnished and that an RO episode has been initiated.
2. (2) Dual participants and Technical participants must bill an RO Model-specific HCPCS code and SOE modifier to indicate that a treatment delivery service was furnished.
3. (3) RO participants must bill the same RO Model-specific HCPCS code that initiated the RO episode and an EOE modifier to indicate that the RO episode has ended.
4. (4) RO participants may submit a claim with an EOE modifier only after the RT course of treatment has ended, except that such claim must not be submitted earlier than 28 days after the date of the initial treatment planning service.
(c) Billing for RT services performed during a clean period. RO participants must bill for any medically necessary RT services furnished to an RO beneficiary during a clean period in accordance with existing FFS billing processes in the OPPS and PFS.
(d) Submission of no-pay claims. RO participants must submit no-pay claims for any medically necessary included RT services furnished to an RO beneficiary during an RO episode pursuant to existing FFS billing processes in the OPPS and PFS.