Hello nomi and welcome,
Cable Cards are always paired with host cable boxes and allocated to a specific physical Comcast location. If you need to have a cable card & cable host box at your other location, you can have another cable box combo installed at that location to get it implemented. Your old location equipment will be needed for return of that equipment to that Comcast account number.
Hope this helps you out.
Okay, if you own the cable box then you should be able to contact 800-391-3000, use technical Video support, then ask the technical agent to pair your box with the cable card and this should get it done for you.