How to Reset Wordpress URL

If you have changed you URL and you can't access any more your site:

1) Edit wp-login.php
Just after the line "require( dirname(__FILE__) . '/wp-load.php' );"
Insert:

//FIXME: do comment/remove these hack lines. (once the database is updated)
  update_option('siteurl', 'YourFirstURL' );
  update_option('home', 'YourFirstURL' );
  

2) Edit index.php to Default

Now you can open on a Browser your First Wordpress URL.

After you need to Remove the lines inserted in wp-login.php

Got it from here:Codex