Creating a CNAME record for each of the domain names or subdomains that you have in the hosting account will allow you to direct 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 it is being redirected to. In this light, you cannot set up a CNAME record to forward your domain name to a third-party provider and keep a working email service with the first hosting provider. Also, it is important to note that a CNAME record is always a string of words and never a number as it is generally confused with the A record of the domain name being forwarded. One of the main uses of a CNAME record is to point a domain address that you own through one company to the servers of another provider if you have created a site with the latter. This way, the website will appear under your own domain name, not under some subdomain provided by the third-party company.