Moving from Premiere to Roamio- need cable card advice

I have Charter and they are pretty inept when it comes to cable cards. Would it be best to try and use my current cable card and try to get a pairing over the phone? I would hate to have to make a long trek to the Charter office to get a card that would still have to be paired or pay for a truck roll. What info would I have to provide? Cable card id and host id? Anything else? Do I have to worry about unpairing or removing card from my account?

The TA is not paired to the TiVo, right? My current TA should work with the Roamio?