I once tried to change my blog from blogs.mysite.com to blog.mysite.com (removing the 's') but my wordpress site didn't want to workd out.
No help anywhere since I had to browse all the config files manually.
But the issue that I saw so difficult worked out to be really easy.
DELETE THE CACHE FILES xD
Then you'll be able to access the /wp-admin/wp-login.php page, log in (the template won't work, but the links are ok), go to options and change the URI of the wordpress home.
Accept the changes, DELETE THE CACHE AGAIN, and type the new URI and it should be fixed.