If a worker would only like to book appointments every 30 minutes, 60 minutes or other, that can be customize by following the steps below:
Click the Menu Icon (≡) and then click Setup > Setup Workers > Worker Details > Services tab
Select the during under Appointment Services Book Every # of Minutes drop down
Click Save
The duration preference will be used for Find Appointment, Modify Search Appointment and Online Booking. Express Booking will not warn the user if the duration is off.