Creating a CNAME record for each of the domain addresses or subdomains you have within a hosting account will enable you to direct it to a different domain/subdomain. The forwarded Internet domain will lose all its records - A, MX and so forth, and will take the records of the Internet domain it's being pointed to. In this light, you simply can't create a CNAME record to redirect your domain to a third-party company and maintain a working email service with the first provider. It's also very important to know that a CNAME record is always a string of words and never a number because it is commonly mistaken for the A record of the domain name being forwarded. One of the main uses of a CNAME record is to point a domain that you own through one provider to the servers of some other provider assuming you have set up a site with the latter. That way, the site will appear under your own domain name, not under some subdomain provided by the third-party company.