Creating a CNAME record for any one of the domain addresses or subdomains you've got in the hosting account allows you to forward it to a different domain/subdomain. The forwarded domain name will lose all of its records - A, MX and so on, and will take the records of the domain it is being forwarded to. In this light, you can't create a CNAME record to direct your domain name to a third-party company and retain a working e-mail service with the first hosting company. It is also important to note that a CNAME record is always a string of words rather than a number because it is often wrongly identified as the A record of the domain name being forwarded. One of the primary uses of a CNAME record is to forward a domain address which you own through one provider to the servers of some other company in case 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.