Hi, diddy. The Reader for Mac software is missing the deauthorize button. It only has rename as an option. You can deauthorize the T1 wirelessly. On your T1 click the Reader Store icon on the home screen. Select Account in the upper-right corner. In the "My Account Overview" list is an item called "Device Settings". Select the Edit button next to it. Then click Deauthorize in the next screen that opens.
Alternatively, you can contact Sony support at 1-877-263-2863. Give them the name of the device and the date that it was authorized.