Setting up a CNAME record for any one of the domains or subdomains you've got in a hosting account will permit you to direct 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 domain name it is being directed to. In this light, you cannot set up a CNAME record to point your domain to a third-party company and maintain a functional email service with the first hosting provider. It's also essential to know that a CNAME record is always a string of words and never a number because it is regularly mistaken for the A record of the Internet domain being redirected. One of the main uses of a CNAME record is to point a domain name you own through one provider to the servers of some other provider in case you have created a site with the latter. By doing this, the website will appear under your own domain name, not under some subdomain provided by the third-party company.