Setting up a CNAME record for each of the domain names or subdomains you've got in a hosting account allows you to redirect it to a different domain/subdomain. The forwarded domain address will lose all of its records - A, MX and so forth, and will take the records of the domain name it's being directed to. In this light, you cannot create a CNAME record to direct your domain to a third-party company and retain 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 often mistaken for the A record of the domain name being redirected. One of the major uses of a CNAME record is to point a domain you own through one company to the servers of another provider when you have created a site with the latter. By doing this, the Internet site will appear under your own domain name, not under some subdomain provided by the third-party company.