I created a wordpress website with its own domain name on my Godaddy account. However, after that domain name expired, I still want to archive the website content as a sub-domain of my account. Then, I created a sub-domain under my main domain name (see acdt2017.defta.org and acdt2016.defta.org as examples). But after I created those sub-domain names and select the correct site folders, the forwarding don’t work. They still linked to the old domain name.
To fix this, I did followed my own post at http://kerdsri.com/2016/05/04/changing-url-for-wordpress/
By adding these two line of code in config.php
Now everything is working correctly ^_^