After having texted a friend or two you looked in the machine a bit more, and saw that there were some dials and switches aside from the "change bodies" button. You told Harry "Hey, there seem to be a few more options with this body change thing... Some switches and dials... Some which say things like Drain/Gain... Age, Size, Gender... Other things... Should we try some of these things out?"
Harry in your body looked and said "I suppose we should test it out... and since our bodies are a bit different right now experimenting with these trait changes should be easy enough to do." He climbed into the other cabin and you saw some of the switches and dials move. You suppose you should let him switch something first and you were at least happy that you could see what change would come on your side. You saw the "swap" button flash as an indication that Harry was ready and you decided to hit the button to switch...