Leave can be partially decline even after approving it. In order to do this, go to leave Calendar. Click on the staff leave that you like to decline.
Clicking on the leave will take you to below page. Click on Decline This Leave
It will then ask for the reason of declining leave. Write the reason and click Decline.
Now, leave is partially declined.
Staff Leave will turn Red in Leave Calendar. This shows that leave is declined.
Please note that you are required to decline one leave at the time. Multiple leaves cannot be declined at the same time.