You can set a reminder for as little as 15 minutes or as far out as 2 weeks. This is a very helpful tool for birthdays, anniversaries, bill dues, or other special events. You will need to set up the reminder when you are setting up the appointment initially. To learn how...
When you are on the appointment scheduling screen, you will check the box for a reminder.

Once the reminder is set, a window will pop up to remind you within the 15 mintues, days, etc that you selected.

To turn the reminder off, you must hit DISMISS ALL. To remind you again, chooze the SNOOZE button.