1. Go to the 'Manage Lists' page under the 'Contacts' module
2. Find the list you want to clone or delete. To clone a list click 'Clone' found in the Clone List column. To delete a list select 'Delete' from the Action column on the far right side.
*Note: If you don't want to delete a list, but you no longer use it then you can deactivate it by toggling it off under the Active column