When you register an account on Appointment Reminder all reminders will be sent 24 hours before the time of the Appointment.

If you wish to change this, follow these instructions.
  1. Login to Appointment Reminder

  2. Click on Account Settings at the top of screen.

  3. Click on Business Settings in left hand navigation.

  4. You will see an option that says "How many hours before appointment we should send the reminder (default 24 hours)".

  5. Change this to your desired time.

If you want your reminders to go at a specific time for example 1pm the day before the appointment then choose the "Custom" option.  In the days before enter 1.  If you wanted the reminder to go 7 days before you would enter 7.

Please note you can also change each individual appointment when creating them in the calendar or in Outlook Calendar.  Setting the default is great way to speed up the process of entering appointments.