A "Walk-in" is a concept first described in ancient Hinduism. The modern name comes from related, but not identical, New Age movements and beliefs. A walk-in is thought to be a person whose original soul has departed his or her body and been replaced with a new soul. The transition generally happens in relation to some traumatic event such as a life threatening injury or disease.
After recovering from the trauma the walk-in may behave quite differently. He or she may speak in an unfamiliar language, with an unusual accent, identify themselves by a different name, be disoriented, be extremely agitated, or even usually calm.
Consider a car that is initially purchased by an aggressive young man. The car is often seen speeding through town, sometimes running red lights, occasionally weaving down the road with its inebriated driver at the wheel. Eventually the young man tires of the car and sells it to the proverbial "little old lady" who only drives to church on Sunday. Now the car rarely reaches the speed limit, seldom actually goes anywhere at all, and is never seen running red lights of weaving down the road. The car's behavior is totally different because there is a different driver behind the wheel. That is the situation with walk-ins except the car is a human body. Of course the degree of difference is not always so profound and recognizable.
To further complicate the matter, the walk-in phenomenon is not necessarily a one way trip. That is, an original soul may leave a body, be replaced for a time and then return. Upon return the temporary inhabitant my leave or the two may coexist for a time. An example of such a swap would be Ansel Bourne (ref. http://www.oldandsold.com/articles19/psychoanalysis-8.shtml).
The Rev. Ansel Bourne was a clergyman with a fine reputation. His health was apparently quite good and there is no indication that he suffered any accident or injury. However he had, since childhood, suffered intermittent and rather extreme depression (the "blues").
One day he withdrew $500 from a bank in Providence, boarded a train car and disappeared for two months. Subsequently his family received a telegram saying that a man claiming to be Rev. Ansel Bourne was in Norristown, Pa., acting strangely. Actually, Ansel was acting rather normally for someone who simply had no idea what he was doing in Norristown.
Six weeks before his reappearance, Bourne had gone to Norristown, rented a small store, stocked it with candy and fruit and had been doing business as A. Brown, living in the back of his shop where he cooked his own meals. He never attracted anyone's attention. He attended church regularly, and once, at a prayer meeting, made a quite good presentation. When his previous personality abruptly returned, he was weak and had lost over twenty pounds. He was also understandably confused about his present living situation.
Psychologist William James (1842-1910) examined Ansel under hypnosis. In so doing, the Brown personality presented itself and insisted that he had no memories or knowledge regarding Ansel Bourne. Brown simply didn't know Ansel Bourne and repeated constantly that he felt "hedged in at both ends." He could not remember any of the incidents prior to getting on the train car, nor any of those following Ansel's resurfacing in Norristown. The only explanation he gave for his escapade was that "there was trouble back there" and "he wanted rest."
In this case the first personality did not know the second, nor did the second know the first. Interestingly, Ansel Bourne was the inspiration for the name 'Bourne' in the novel and movie series "The Bourne Identity."
Most walk-in situations do tend to be one-way experiences. In these cases the first identity or soul seems to have permanently vacated the body. It could be speculated that the first soul completed what it was here to do, found this life was not what it was looking for, found the experience here too difficult, or just got fed up with whatever was going on and decided enough is enough.
In many cases the switch to the new personality is not dramatic or abrupt. It's as if the new personality enters the body with a little amnesia itself and simply tries to adapt itself to the existing identity of the body. In so doing the differences emerge somewhat gradually while the body continues to present itself as the same person it was previously. In such circumstances sometimes checklists are used in an attempt to determine if a walk-in has taken place.
Checklists can include things like whether the person now wishes to be known by a new name or nickname, if a significant career change has taken place, if the person has suddenly developed a profound new interest in the study of psychic phenomena, a feeling that one is an alien or out-of-place, or a sudden desire to move to a new environment or longing for a place to which one has never been.
Sometimes checklists to determine walk-in status include things like reported memory loss, the sudden onset of allergic reactions or phobias. However, since all of these factors could possibly be attributed to normal life changes, it remains difficult to determine if a walk-in has actually occurred. Since most walk-ins appear to be related to traumatic events, a deciding factor can be determining if any such specific event seems to be the focal point connected with the change in personality. Events such as traumatic injury, surgery, and extreme illness tend to be predominant factors. However, there is simply no known scientific method to prove whether or not the walk-in experience has any objective reality, let alone how to determine with certainty if one has occurred.
Another factor may be an increased spiritual aspect of the person having experienced the walk-in phenomena. In popular culture it is speculated that only those souls who are more advanced in a spiritual sense can enter and inhabit an adult body. Most can only enter slightly before, during, or immediately after physical birth. So, if someone becomes much more compassionate, loving, or spiritual after a traumatic life-threatening event, this may be a key factor in determining if a walk-in has taken place.
As confusing as this might be for friends and relatives, it can be equally confusing for the one who is involved in the walk-in. This is because it is apparently not unusual for the walk-in to be fully cognizant of the history, memories, and experiences of the body they have recently come to inhabit. In a sense, all the files and records are left behind for the new owner. The walk-in might have no problem "remembering" their childhood, but at the same time not "feel" that it is actually "their" childhood. They may remember people but no longer have exactly the same feelings toward them or relationship with them that they remember having in the past. Kelemeria Myarea Elohim, who claims to be a walk-in, explains her perspective on this (ref. http://www.salemctr.com/newage/center14.html).
Q: "When you came into this new body for you was there any cellular memory that had been left behind?"
A: "Oh yes! The person's memory is still in the body. And what she hasn't completed I now have to finish for her, all the negative patterns and left-over stuff that a person has. Plus on top of that you have your own issues to take care of. It's an interesting challenge trying to take on two sets of things."
Q: "What about your friends before the walk-in event 3 years ago?"
A: "They know I've changed. After things settled down I told them all about it. I told them I wasn't the same person, and that they didn't know me the way they used to. Some people just went out of my life because they couldn't handle it. As you change new people come into your life. The friends I have now that I've made over the last couple years are completely different from the people I knew before.
"Some people just can't handle it when I tell them who I am. They're living in fear. How are they going to handle something like this? I tell people that I've never been on this planet. I've never had an Earth background. I am now integrated in this body so I am now human. I am an earthling at least in body. I will never be completely human. But I have completely integrated into who I now am. A lot of walk-ins don't know what happens. It's a frightening experience. They have no idea what has happened to them."
The movie "K-PAX" (2001) presents many of the basics of the walk-in phenomena. So, perhaps being a walk-in is adequately summed up by Prot (K-Pax, 2001), "I will admit the possibility that I am Robert Porter, if you will admit the possibility that I am from K-PAX. Now if you'll excuse me, I have a beam of light to catch."