Creating a stand-alone site from a WordPress sub site

Basically all you need to do is to import all the posts/pages from the sub-site to a new URL.

1. First you will need to setup a new, fresh WP install e.g
   example.local (on localhost),
2. then you need to export all the contents from your website (e.g example.com) on remote server,
3. finally import all the contents (using XML file from step 2) to example.local

Once you have finished step 3, and eveything looks right, you can

4. move domain example.com to your own server,
5. export the script and database from example.local,
6. and import them to the server,

and if things went smooth, you can ask your friend to remove the subsite from her site.