The best way would be to use a vacuum fluid recovery tank. Have a nifty one called "vacula" and feed the hose down the Dipstick tube. If that's not an option just get under there with the engine cold and loosen the drain plug and let it drain the appropriate amount. I wouldn't think too much into your engine being hot. There might have been a required test drive after the oil change and it was at operating temp when they handed you the keys.