Trying to cancel my registration so my buyer can install True Image 2013

Over a year ago I moved to a different brand of backup software. The True Image 2013 has not been on my computer since I upgraded to an SSD.

I recently sold it on Ebay and when the new owner tries to install it he gets a message saying that the original owner (me) needs to cancel registration.

I have scoured the the knowledge base and find no way to do this. Any help would be greatly appreciated. The buyer has forwarded the key code to me in case I need it to cancel.

Thanks