Creating a CNAME record for each of the domain addresses or subdomains that you've got in a hosting account will permit you to redirect it to a different domain/subdomain. The forwarded Internet domain will lose all its records - A, MX and so on, and will take the records of the Internet domain it's being directed to. In this light, you can't create a CNAME record to point your domain name to a third-party company and maintain a functional e-mail service with the first hosting provider. Additionally, it is very important to know that a CNAME record is always a string of words and not a number as it is regularly wrongly identified as the A record of the Internet domain being forwarded. One of the major uses of a CNAME record is to forward a domain name you own through one provider to the servers of some other provider in case you have set up a website with the latter. In this way, the site will appear under your own domain address, not under some subdomain provided by the third-party company.