How to archive a website out of the database?

I’m wondering if there is a way to remove a website from Piwik and download it as an archived file. Then say if i wanted to later, re-import the file and get the site back with it’s historical data?

We use a single install of Piwik for some clients, but if they leave we don’t want to delete everything we’ve tracked up until now. Is there a way to handle this?