Setting up a CNAME record for each of the domain addresses or subdomains that you have in the hosting account will allow you to point it to a different domain/subdomain. The forwarded domain name will lose all of 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 forward your domain to a third-party provider and retain a functional email service with the first provider. It's also essential to know that a CNAME record is always a string of words and not a number as it's commonly wrongly identified as the A record of the domain being forwarded. One of the primary uses of a CNAME record is to point a domain address which you own through one company to the servers of another company if you have set up a website with the latter. That way, the site will appear under your own domain, not under some subdomain provided by the third-party provider.