That depends on each carrier. For example, on the Medicare application you have indicated the date he was going to begin seeing patients on the application. So he would be able to see patients during the time the application was in process but hold the billing until the application was approved. Some insurance carriers date the participation based on when the application was received, some date them based on when the contracts are signed, and others based on when the process is complete. So on the commercial carriers, it all varies. You can still file the claims though, the patients may have out of network benefits.Michele