Creating a CNAME record for any of the domain names or subdomains you have within a hosting account will permit you to forward it to a different domain/subdomain. The forwarded domain will lose all its records - A, MX etc, and will take the records of the domain it's being redirected to. In this light, you can't set up a CNAME record to forward your domain to a third-party company and keep a functional email service with the first hosting provider. Also, it is 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 main uses of a CNAME record is to forward a domain address which you own through one company to the servers of another company assuming you have set up an Internet site with the latter. This way, the Internet site will appear under your own domain name, not under some subdomain provided by the third-party company.