Change Reminder Times

1. Select Tools > Options from the main menu.
 
2. Uncheck the Default reminder box to not use reminders.
 
3. Leave the box checked and select a new reminder time to change the default reminder setting for all meetings and appointments.
 
Change Reminders in Existing Meetings and/or Appointments
1. Double-click a calendar item to open it.
 
2. Uncheck the reminder box to remove a reminder.