Yes, whether you place an order by telephone or via our secure online order form, be sure to specify that you are requesting a transfer and NOT a new domain. You should keep the service at the present site while waiting for InterNIC to complete the transfer. We will provide you with a unique IP address so you can mirror the site on our server.
When the transfer is compete there is a 72 hour propagation period where visitors could go to either site. At the end of the 72 hours you should contact the previous host to have them delete the old domain from their DNS record. If you use this same provider for your Internet access you will not be able to access your site at SiteServer with the domain name until they update their DNS record.