RHN to RHSM for existing RHEL 6 Servers

We are not ready for Satellite 6 yet and currently we are getting OS updates from RHN for our RHEL 6 servers. However, RHN is being shutdown in July. So, how can we migrate existing RHEL 6 servers to RHSM and start getting the same updates from RHSM instead of RHN? We are not going to migrate to Satellite 6 yet.