User profile in ADUC and changing domain extension name

We are adding one of our remote sites to a different domain and want to be able to keep or switch the users’ profile information and data “Internet Favorites”, “Desktop Items”, etc…to their new profile once their workstation is in the new Domain and their profile has been created on the local computer. I have heard of a way that you can change the newly created profile, with the “username.DOMAINNAME.LOC” to .OLD and then rename the users origanal profile to .DOMAINNAME.LOC. Has anyone heard of this? I have tried on a test account, but get access denied.