Creating a CNAME record for any one of the domains or subdomains you've got in the hosting account will permit you to forward it to a different domain/subdomain. The forwarded domain name will lose all of its records - A, MX and so forth, and will take the records of the domain it is being redirected to. In this light, you simply can't create a CNAME record to point your domain name to a third-party company and maintain a functional email service with the first hosting company. Also, it is important to note that a CNAME record is always a string of words and never a number as it's often confused with the A record of the domain address being redirected. One of the primary uses of a CNAME record is to point a domain name which you own through one company to the servers of another company assuming you have created a site with the latter. That way, the website will appear under your own domain address, not under some subdomain provided by the third-party provider.