There are certain things that you may do after a primary domain name change in order to preserve your page ranking. However, please bare in mind, that these methods may not be 100% effective and some loss in page ranking is to be expected but it is still preferable to starting from scratch.

The first thing you will need to do is ensure that both domains are up and running simultaneously – simply park your old domain name to your new one.

Once that is done, you will need to create a permanent (301) redirect from your old domain name to your new one. This will ensure, that if a vistors clicks on an outdated link in a search engine, he will still be able to view the content of that page. This will also help in instructing search engine bots to look for your website at the new domain name.