Emercury has a feature where you can convert your regular list to a suppression - that means all recipients which were in this list will be added to a new suppression list. The Audience is not deleted when we convert to suppression we only add new suppression list.
Click 'LIST' and under list actions select 'CONVERT'.
Select a list(s) by placing a checkmark in the box and hit the 'CONVERT' button.
Name your suppression list and click 'Done', you will see Lists converting has started.
To verify if the list has been added go to LIST then select 'Suppression' and look for the list name and click view list contacts.
