Call Customer Services on 150 from your ntl phone line, or 0845 454 0000 from another line. I believe the first change is free, but don't quote me on that!
As for changing the name, yes you can request it on the same call but some proof of the change will be required (a Change of Name form will probably be posted to you). If it's just a misspelling, it can probably be done over the phone.