It’s how you say it

Has your front-desk ever double-booked patients? When this happens, you inevitably start to run behind and keep patients waiting.
One solution is to call the double-booked patient and ask him to reschedule. But that is not always a good solution, since the patient may cancel instead of reschedule.
A better solution: Call the patient and say, “This is a courtesy call to let you know I am running behind schedule by 15 minutes.”
Then ask, “Is it convenient for you to arrive 15 minutes later to avoid waiting?”

— John Hinwood, DC
Powerful Practices, www.powerful-practices.com