Most (if not all) people seem to be able to swap Verizon cablecards and/or Tivo's without any hassles (as long as it's Verizon Fios and not Frontier Fios territory.) I've had no problems doing this.
If pairing is necessary for some reason, as long as the cablecard isn't faulty pairing should be able to be done over the phone with tech support.
If pairing is necessary for some reason, as long as the cablecard isn't faulty pairing should be able to be done over the phone with tech support.