Creating a CNAME record for any one of the domain names 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 its records - A, MX etc, and will take the records of the domain name it is being redirected to. In this light, you can't set up a CNAME record to forward your domain to a third-party provider and retain a functional email service with the first provider. Also, it is very important to know that a CNAME record is always a string of words rather than a number because it is commonly wrongly identified as the A record of the Internet domain being forwarded. One of the major uses of a CNAME record is to point a domain that you own through one provider to the servers of another company if you have created a website with the latter. By doing this, the website will appear under your own domain address, not under some subdomain provided by the third-party provider.