When booking time off within Natural HR, there is the option to select whether or not the request is for a full day, just the morning (AM) or the afternoon (PM). 

To enable the AM/PM selection, from within an administrator account, you will need to go to:

Administration -> Company -> Settings -> Time off settings (global)

 In the 'Self service' section, to enable AM/PM selection, both of the following fields must be set to 'Yes':

• 'Allow employees to enter time off days/ hours'  - as employees must be able to type 0.5 if calculated in days or the number of hours in the duration box. 
• 'Allow employees to specify AM/PM for half day bookings'

Once these fields have been changed, click on the 'Submit' button to save the changes. 

When booking time off an employees will not have the Period option which allows them to select AM or PM 

If a half-day request has been submitted, this will be indicated with AM or PM on the employee's and Admin, HR and manager's calendars.