2004 GMC Envoy Owner's Manual - Page 96

To release the parking brake, hold the regular brake pedal down. Pull the parking brake lever up until you can press in the button at the end of the lever. Hold the button in as you move the parking brake lever all the way down. Notice: Driving with the parking brake on can overheat the brake system and cause premature wear or damage to brake system parts. Verify that the parking brake is fully released and the brake warning light is off before driving. If you are towing a trailer and you must park on a hill, see Towing a Trailer on page 4-55. That section shows what to do first to keep the trailer from moving. 2-30