This has been the biggest pain point for most patients, for a long time now. You can use free online scheduling software and apps that will empower patients to book and reschedule appointments. You can even use your EMR's appointment scheduling abilities. It's very easy to use ZocDoc, google book now, facebook book now etc. Whatever tool you use, the most important thing is to give the patient a confirmed appointment ASAP. Otherwise, the patient is simply going to move on to the next practice.