You can do it on a milling machine or a drill press if your really careful. Just need to lay it out properly and put the holes in between the existing ones. The holes can probably be a little sloppy because the center register of the hub locates the rotor not the lug bolts. From your post though it seems like your not very experienced with stuff like this? Why would you want to in the first place? New rotors are pretty cheap to buy new ones. Probably cheaper that the price of having someone redrill yours.
Huntington Beach, CA