Creating a CNAME record for each of the domain names or subdomains that you've got in the hosting account will allow you to direct it to a different domain/subdomain. The forwarded domain will lose all its records - A, MX etc, and will take the records of the Internet domain it is being redirected to. In this light, you cannot create a CNAME record to forward your domain to a third-party company and maintain a working e-mail service with the first hosting provider. It's also essential to know that a CNAME record is always a string of words and never a number as it is generally wrongly identified as the A record of the domain name being redirected. One of the major uses of a CNAME record is to point a domain address that you own through one company to the servers of another company if you have created a site with the latter. In this way, the site will appear under your own domain address, not under some subdomain provided by the third-party provider.