You can do this with a redirect. You will need to go to the old site's cPanel (control panel) interface and then go to "Redirects". Set the old site's index page to redirect to the new site's index page.
Alternatively, if you wish for the old site and the new one to go to the same place but have not set up the new website yet, you can use a parked domain. A parked domain allows you to add a second domain name to your Host Color account that goes to the same website.
Example: If you currently have myforums.com and you want to add the domain mynewforums.com which also goes to theÂ myforums.com site, simply addÂ mynewforums.com as a parked domain and both domains will direct to the same place.