A private doctor is independent of any insurance. Thus, with a private doctor you neither need a health insurance certificate nor a referral nor an e-card. The services are directly charged to you. Usually the costs are at least partly refunded by many insurances. The amount of the refund depends on the kind of service and on your insurance. If a previously scheduled appointment is not cancelled, or is not cancelled in time to allow it to be offered to someone else, the corresponding fee must be charged.