This action can only be performed by admins in the enterprise. To delete a line:
Navigate to "Manage Lines" from the menu on the left side of the screen
Click on the name of the line you want to delete (it can't be the line you are logged into)
Click on "Edit User”
Click on “Delete Line”
Note: Once you click “Confirm,” there is no undo.
Note 2: Only account admins can delete lines. If you do not see the "Manage Lines" option on the left menu, you do not have admin rights and must request this to the user with admin rights in your enterprise.
Note 3: If you want to delete the line you are logged into, log out of this line and login with another admin line from your enterprise. This way you will see the 'Delete Line' red button as an option.