how to change coolant?

I have a '99 3.5L and wanted to ask for suggestions on how to change the coolant. Is there an engine coolant drain plug? If I only want distilled water mixed with the new dexcool, can I just drain and replace the coolant (no flush)?

Thanks

The coolant drain is on the bottom of the radiator. Just drain it untill it quits then close the petcock and fill with premixed dexcool or mix the 50/50 type dexcool with water. There shouldn't be a need for a flush.