Setting up a CNAME record for any one of the domain addresses or subdomains you've got in a hosting account will allow you to point it to a different domain/subdomain. The forwarded Internet domain will lose all of its records - A, MX and so on, and will take the records of the Internet domain it is being redirected to. In this light, you simply can't set up a CNAME record to redirect your domain name to a third-party company and maintain a functional email service with the first provider. Also, it is essential to know that a CNAME record is always a string of words and never a number as it is regularly mistaken for the A record of the domain address being forwarded. One of the main uses of a CNAME record is to point a domain name that you own through one company to the servers of another company if you have set up 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 company.