swingbed billing for NEPHROLOGIST

Hello, can my physician(a nephrologist) see a dialysis patient that has been transferred from "inpatient" to "swing bed" and bill for it? I found the codes and the POS that is required for billing swing bed, but my doctor does not think he can bill for this. Can primary doctor and my physician (nephrologist) bill on same day? Thank you for you assistance, any help is very much appreciated!!!! Anita