I have a provider that recently left employment at a local facility. He is now in a group practice we bill for. My question is how to take care of his post op patients. Should we be billing E/M codes with modifier 55 or should we bill 99024? My issue is that the facility got paid for his taking care of the patients from pre op to surgery to post op, however, he isn't doing that post op care under their tax ID#. If you can refer me to specific citations about this, I would appreciate that as well.