This functionality allows you to inform your organisation if you are available for the day and for how long.
If you have the permission to set yourself on/off call this will show at the top right-hand corner as shown on the image below.
Click the arrow key and set the on-call time by selecting the hours and minutes.
You will be automatically set off call when the set time has elapsed. You can end your on call status at any time by clicking the on call button and selecting the Show as "off call" option.
You and your supervisor/named manager can see that you are on-call and for how long on the user banner on your "User Details" page.