As Erik said, you can import the list and then delete - but you'll lose all data for reporting. You could export, though, before deleting so that you have a backup record.
I think the broader question to ask surrounds the purpose of the one-off. Is this just operational? Or is this a list that you're trying to gain opt-in permissions?
If you have permission to email once (but want them to take action for future marketing) you can monitor who clicks/engages/opts-in. At that point, when you delete the list, you'll want to exclude those who took action since they have now opted in to future messages.
Not entirely clear if the above scenario is the purpose of your one-off email, though.