Short answer: You can't, and you shouldn't.
Long answer: Removal or alteration of a VIN number is extremely illegal. It's also extremely difficult. Your VIN number is printed or etched in multiple locations throughout the vehicle. Most vehicles have three or four such locations, with one of them usually being in a deeply hidden location that is - theoretically - known only to the manufacturer and law enforcement agencies.
Additionally, some of these VIN locations may be on sensitive or easily damaged parts of the vehicle. These are the most common places:
Firewall of the vehicle
Radiator Support Bracket
Dash by windshield
Left hand inner wheel arch
Guarantee & Maintenance Book
Machined Pad on front of engine
Drivers door or post on passenger side
Additional locations include the interior frame, gas tank, etc. These are often under the body work or deep up inside the undercarrage. They are intended be used for forensic identification rather than on immediate inspection. So, they are difficult to find unless you know exactly where they are.
If you know where all your VIN locations are, you can theoretically remove them all. This would be difficult, for aformentioned reasons, but it is possible. To CHANGE the VIN, however, would require the identical parts from a similar vehicle. This doesn't change your VIN so much as take someone elses. And since the new parts would most likely have to come from a stolen vehicle (No garage or scrap yard will sell all of the necessary parts, such as the dash-plate), it wouldn't help you much.
Additionally, the VIN itself cannot be altered in-place. Not only would such an alteration be extremely difficult even for an expert forger, it would be easily found. If you were to, for example, turn a 6 into an 8, the check digit would not longer be correct. This would be caught instantly, were the VIN to be entered into a computer system.
So, all in all, it boils down to the short answer: you can't. Even if you can, it's extremely illegal, difficult, easy to catch, and won't get you much.