There are a number of reasons you may want to change your domain name.
For example your company may change it’s name, your may be re-branding, you may have forgotten to renew your domain and lost it, you may be building the site with a temporary domain name but for whatever reason, it can be edited once your site has been built.
Before you start always take a full backup of your WordPress site because things can go wrong so you need a point in time to restore back to.
Click Here for information about How to Backup your WordPress Site.
There are 3 options to do this change, you can edit the general settings of your site, edit the wp-config.php file or directly change your database. They are ordered in ascending order of difficulty.
Option 1: Edit General Settings
Within the WordPress Dashboard, Click Settings > General and you will see the WordPress Address(URL) and Site Address(URL).
To change the domain name, simply change the URLs in these two areas.
BE WARNED: As soon as you do this, your blogs address will be changed, if you do not have your domain configured correctly, you will not be able to login.
Option 2: Edit wp-config.php
The second way to change your domain name (and easiest to fix) is to set two new entries in your wp-config.php file.
Edit this file using the ftp client of your choosing and add the following two lines
These entries correspond to the two URLs from method one. Enter your new domain name and save the new wp-config.php. When you attempt to access the old domain you will be re-directed to the new one. If you are having problems, simply remove these two lines and you will have access to your old domain.
Option 3: Edit The Database Directly
This one is a bit more advanced, but if you are happy editing your WordPress database with tools like phpmyadmin then this is another way to change your domain name
Navigate to your wp_options table, it may be called something like wp_options and find the two entries siteurl and home.
Edit these database entries with your new URL sand save them to the database.
Call 1-800-622-4403 option 2 and request Professional Services for Premium WordPress support.