Setting up a CNAME record for any of the domain names or subdomains that you've got in the hosting account will enable you to forward it to a different domain/subdomain. The forwarded domain address will lose all its records - A, MX etc, and will take the records of the domain it is being redirected to. In this light, you can't create a CNAME record to forward your domain to a third-party company and retain a functional email service with the first provider. It's also important to note that a CNAME record is always a string of words and not a number as it's regularly confused with the A record of the domain name being forwarded. One of the primary uses of a CNAME record is to point a domain address which you own through one company to the servers of some other provider if you have set up an Internet site with the latter. This way, the website will appear under your own domain address, not under some subdomain provided by the third-party provider.