The Changeling Way was a means for True Fae, mostly of commoner Kiths, to deal with the rising Banality of the Mundane world as the Mythic Age ended, turning themselves into the forerunners of modern Changelings.
These fae transferred their souls into (often infant) humans, leading to the traditional myth of fairies stealing away a human child to replace it with a child of their own. Safely embodied in mortal flesh, these new hybrid beings were protected from banality and able to interact with both the Near Dreaming and with the human world, as fellow humans. Most Changelings now, however, are born naturally, the fae soul migrating to another body at death.
The Changeling Way was taken by nearly all Commoner Kiths, although the Sidhe of House Scathach also partook. In contrast, the Gallain (such as the Nunnehi and Menehune) found highly spiritual people, like mediums and shamans, with whom they shared bodies and were later passed on into the children of these people, binding themselves to specific tribes. The Shinma have the kon shou, also known as the Gift of the Chien, in which they take the body of a person near death as their own. The Adhene, who are at large relatively new to the Autumn World, have no such protection and have to take human bodies by slipping into the dreams of sleeping persons. Otherwise, they have to use Glamour to provide a shell against Banality.