By default, the minimum increment of time off that users can book off in Replicon is a full day. If you want to change this increment and allow users to book off partial days:
Users may make bookings using parts of hours (for example, 0.75 or 2.25) or full hours. They can also book off 1/2 or full days.
Users must make bookings using full hour increments (for example, 1, 2, or 4 hours), or full days
Users can book off 1/4, 1/2 or full days only
Users can book off 1/2 or full days only
Users can book off full days only