[CAN I DO IT]

I Need To Change A Dryer Power Cord From A 110 To A 220(from A 4 Prong To A 3 Prong). When Putting On The Jumper Wire---on End That Goes To Dryer Frame--do I Leave The Already Present Ground Wire In Place And Add The Jumper Or Do I Remove The Ground Wire? If So What Do I Do With It? The Other End Of The Already Present Ground Wire Goes Up Into Dryer.