How do you change coolant in a 1999 Porsche carrera?

To change the coolant in a 1999 Porsche Carrera, start by ensuring the engine is cool and then locate the coolant reservoir and drain plug. Place a container under the drain plug, remove it to let the old coolant drain out, and then close the plug once drained. Next, mix the new coolant with distilled water as per the manufacturer's specifications, fill the reservoir, and run the engine to circulate the coolant, checking for leaks. Finally, top off the coolant as necessary and ensure the system is properly bled of air.