Where would you begin this transfer?

First make sure your domain administrator is a schema adinistrator. Then using the Administrative Tools folder, open the Active Directory Users and Computers; right click on the icon next to it, and press Connect to Domain controller.

Choose the target domain that will be the new role holder. Press OK. Right click again and press Operation Masters. Now you must find the tab that represents the role you want to transfer, press Change and then OK to confirm the change.