Creating a CNAME record for each of the domain addresses or subdomains you've got in the hosting account allows you to direct it to a different domain/subdomain. The forwarded domain address will lose all of its records - A, MX and so forth, and will take the records of the domain name it's being directed to. In this light, you can't create a CNAME record to direct your domain name to a third-party provider and keep a working email service with the first hosting provider. It's also very important to know that a CNAME record is always a string of words and never a number as it's commonly mistaken for the A record of the domain being redirected. One of the major uses of a CNAME record is to point a domain address that you own through one provider to the servers of another company if you have created an Internet site with the latter. This way, the Internet site will appear under your own domain address, not under some subdomain provided by the third-party company.