I am in the process of upgrading our GW system to 2012 and cleaning up some unneeded stuff in the GW system. I have a secondary domain running with the post office off of it that is no longer needed. I deleted the post office already. Now, the documentation says you can just delete the domain if there are no subordinate objects off of it, which there aren't, but then I see articles on going through a process of releasing it and then creating external system and then deleting it. What is the difference between the two procedures and in my case can't I just connect to priimary domain and delete the secondary objects?