Conversion and the Soul

If a person is born with the soul he or she has, and that is what they are (in essense), then how is it possible for someone to convert, change their non-jewish soul into a jewish one?

According to the Kabbalists the "soul" is actually comprised of five components, Nefesh, Neshama, Ruach, Chaya and Yechida. Ech human being has at least three of these parts and Jews have all five. When a person converts the two other parts are added to the existing soul. What is fascinating is that the Kabbalists teach that the two parts of the soul that are uniquely Jewish are not a part of the body but, rather they exist above the person and serve as conduits to connect the person in a more direct way to God.