1. Turn on the ignition but do not start the engine.
2. Press and hold the "OK" button on the steering wheel.
3. Press the "Volume" button on the steering wheel until you see the message "*Service now* Reset" appear on the screen.
4. Press and hold the "OK" button for a few seconds until you hear a beep and see a message indicating the service reminder has been reset.
5. Turn off the ignition.
Please note that this procedure may vary slightly depending on the specific equipment and model year of your Mercedes C63. If you are unable to reset the service reminder using these instructions, you may need to refer to the vehicle owner's manual or contact a certified Mercedes-Benz service center.