You can cancel a leave that has not started yet, or end one that is under way early. You will be asked for a short reason.
Steps
Open your profile: on Home, click Leaves on your profile card. You land on Work Info → Leaves.
Switch to the Leaves tab, then to the table view with the grid icon.
Find the leave (it is marked Upcoming or Ongoing), click … in its row and choose Cancel leave.
Enter a Reason and click Cancel leave.
The leave stays in the list with the status Cancelled, so there is a record of it.