Lift the e-brake one click. It seems the same sensor that lights the indicator on the dash also puts the car in rwd mode.
I am a skidpad instructor for PCA. For years we could not do much with Turbo 997s. The awd makes them want to understeer. If oversteer is initiated, the steering goes numb and it’s nearly impossible to maintain yaw angle for any length of time. But, we learned a few years ago about the e-brake trick. 1 click is not enough to create any friction but, sure enough, the car reacts just like any other rwd Porsche!