repairing rotors on 2005 Porsche Cayenne

We have a Porsche Cayenne that needs new rotors. The dealer said the rotors on a Porsche can not be machined and repaired. Is that true?

Asked by for the 2005 Porsche Cayenne
Its been my experience on some cars and SUV's you machine the rotors and they warp very quickly again.Perhaps your dealer has had too high a number of come backs after having machined rotors only to have customers return complaining of brake pedal vibration. Phone several Porsche dealers and see what there policy is on machining or replacing rotors.