How to Change Domain Name
Since it’s not really possible to change domain name of Joomla website directly in administrator control panel, only way to do this is by editing configuration file. As the most important settings being saved specifically in the configuration file named “configuration.php” you can easily adjust domain name as well.
In order to change domain name simply login to the hosting account control panel and use built in file manager to browse through Joomla files. It’s also possible to access these files through FTP. Once you are in place where Joomla files are located, open file “configuration.php” for editing. Usually this file is located in the public_html directory of Joomla installation. Then locate the following line:
public $live_site = 'http://domain.com';
Change domain name to the new one and save the file.