To delete a department:
Go to Contacts and click Directory to open the business directory structure
Click Edit in the top right corner of the main Directory dashboard. Edit, Delete and X buttons will appear in each department and sub-department
Choose the department or sub-department you want to remove and click Delete. The pop-up window will open

Tick the box under the question if you also want to delete the nested sub-departments and contacts

Choose Delete if you are sure that you want to remove the department. Choose Cancel if you changed your mind
After deleting, the department will be removed from your Directory.
If you wish to Edit the department or structure instead of deleting it, check out this guide.