Many a times, one of my colleagues takes up a terminal session to a Windows server for some POC in the Lab. The problem is Windows provides licenses for upto 2 terminal connections to the server. In such a case, if you want to administer or even work on your stuff. You are forced to make a trip to the Lab or the data center to connect to the server and start the terminal manager and kill some of the sessions, this was the way I knew, until NOW.
the best way is to use mstsc /admin option to start the terminal service client in your computer and then you will be able to connect to the server even if both the terminal services are taken by other users. You can then choose to administer the server or log off unused sessions. Well this saves me a trip to the Lab.