Setting up a CNAME record for each of the domain names or subdomains you've got in the hosting account will permit you to forward it to a different domain/subdomain. The forwarded domain address 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 can't set up a CNAME record to direct your domain name to a third-party company and keep a working e-mail service with the first hosting provider. Additionally, it is important to note that a CNAME record is always a string of words and never a number as it's regularly wrongly identified as the A record of the domain address being redirected. One of the major uses of a CNAME record is to direct a domain which you own through one company to the servers of some other company when you have created an Internet site with the latter. That way, the Internet site will appear under your own domain address, not under some subdomain provided by the third-party provider.