Of course you can. Just call Comcast and tell them what you want to do. They may try to make a deal with you, to keep you on the cableTV, if you like the deal, fine. If not, stick to your guns and come away with just internet and phone and no cable TV. Call 1-800-934-6489 (1-800-XFINITY).
Hi kcaslin2, can assist in reviewing current promotions with you if still needed. Please send me a private message with your account information (your name, and phone number).