In MS, how do I move the primary site to a subdomain?

I had a single install of WordPress with my theme, content, etc. I converted my install of WordPress to a MS install in prep for more sites, WordPress made my former single-install-site the primary site (ie if you go to you go to this site). I have another subdomain site setup too (

Is there a way that I can make the first site a subdomain site and make a new landing page for the baseurl?

So there are two sites: site1, site2 and one domain:

Right now my structure is: and (which is the theme/content for site1). I want to get to:, and (which will be a frontpage for the blog network)

Any advice?