This is based on my limited knowledge,,,
The party that gave you the device does not need to do anything.
There is a key-stroke combination you can enter to Adobe ADE to deregister your device. I suspect doing a full reset through the device setup menu will work also. The next time you connect it will step you through registering.
To register you will need an Adobe issued ID - get that first.
http://www.adobe.com/products/digitaleditions/
The Adobe installer has a setup assistant that will get you an ID.
Robert