Setting up a CNAME record for each of the domains or subdomains that you've got in the hosting account will permit you to redirect it to a different domain/subdomain. The forwarded Internet domain will lose all of its records - A, MX and so forth, and will take the records of the domain name it's being redirected to. In this light, you can't set up a CNAME record to redirect your domain name to a third-party company and maintain a working e-mail service with the first provider. Also, it is essential to know that a CNAME record is always a string of words rather than a number as it's regularly wrongly identified as the A record of the domain name being forwarded. One of the main uses of a CNAME record is to forward a domain that you own through one company to the servers of another company in case you have set up an Internet site with the latter. By doing this, the website will appear under your own domain, not under some subdomain provided by the third-party provider.