Change the look and feel for a specific site

I have a site within a SharePoint 2013 site collection that I would like to completely modify the look and feel for. To my understanding, this is done in SharePoint Designer 2013, using the Master Pages tab. However, I would like to know if it's possible to make drastic changes to one site that is within a site collection without modifying the rest of the site collection? Otherwise, I will have to migrate this site to a fresh site collection.