Setting up a CNAME record for each of the domains or subdomains you have within a hosting account will allow you to forward it to a different domain/subdomain. The forwarded domain name will lose all its records - A, MX and so forth, and will take the records of the domain address it is being pointed to. In this light, you can't set up a CNAME record to redirect your domain name to a third-party company and keep a working e-mail service with the first provider. Also, it is essential to know that a CNAME record is always a string of words rather than a number as it is regularly mistaken for the A record of the domain name being redirected. One of the major uses of a CNAME record is to point a domain that you own through one company to the servers of some other company when you have created a site with the latter. In this way, the website will appear under your own domain, not under some subdomain provided by the third-party provider.