http://customersupport.tivo.com/knowbase/root/public/tv090601.htm?
How Do I Transfer My TiVo Service to a New Owner?
Choose the type of TiVo service you want to transfer:
Monthly service You must first cancel your monthly service: to do so, please contact TiVo Customer Support at 877-367-8486 between 7:00 AM and 8:00 PM PST. The new owner of the TiVo Digital Video Recorder (DVR) must then activate service on the DVR. To activate TiVo service, go to tivo.com/activate.
Product Lifetime service Remember that Product Lifetime service accompanies the DVR, not the person. For more information on Product Lifetime service, see Product Lifetime Service. To transfer your Product Lifetime service to a new owner, either you or the new owner must call TiVo Customer Support at 877-367-8486 between 7:00 AM and 8:00 PM PST. If you call, please have the contact information available for the new owner.