Hover over Menu and select Organisation and Users.
Click on the Organisation/Organisation Units until you find the Unit you wish to delete. Click on its link.
Click on the Details tab, then click on Delete at the bottom right-hand side of the screen.
If you still have users or child units within the organisation unit you are trying to delete, you will see the following error.
If the unit is clear however, you will receive the screen below. Click Yes to confirm the deletion.