Yes, you can move the certificate between web sites.....and servers if needed.
If you contact our support team they will be able to advise how to do this.
The instructions differ from web server to web server.
Checkout our FAQs.....they may have what you are looking for:http://www.instantssl.com/ssl-certificate-support/server_faq/ssl-server-certificate-index.html
Head of Global Support and Customer Care Manager