If it's female, it's already err, feminized. If you cause it to start producing MALE flowers, it's then a hermaphrodite (in practical terms, at any rate).
Do be cautious in regards to what you spray on your plant in order to do this, as some of the various substances probably shouldn't be consumed (should say in the thread if the thing the thread discusses is like that, and if you purchase one of the "reversal" products it will (or at least should) state on the bottle if what gets sprayed shouldn't be eaten/smoked.
BtW, you shouldn't have to treat an entire plant - if you spray one branch and it grows a few male flowers, you will be likely to produce many seeds.