Not all walk-in events are soul exchanges/swaps. Many times a higher version of your soul or future self may walk into your body for a short time to help you raise your current frequency and assure you are on track for a certain wave of the collective ascension.
These events are bringing downloads that upgrade our bodies to release density and hold a higher band of frequency on the light/color spectrum of the crystalline structure of the light body. Our physical bodies may respond with discomfort during the adjustment phase much like when orthodontic braces are put on the teeth. The discomfort only lasts until the new alignment is reached.
A lesser-evolved aspect of your soul may also blend for a while in order to raise its frequency enough to be integrated into wholeness with your entire soul essence. This causes the feeling of discord or the déjà vu of "I have dealt with this ten times already. I thought I was done dealing with this issue!"
Soul fragments that left during trauma in this life or a previous one are also returning to be integrated. Their outstanding issues need to be resolved even though we may not remember what caused them or know why they left in the first place. These aspects will make their needs known--sometimes in a disruptive way to get your attention. This is inner child or shadow work. No need to focus on what is "wrong" or how/why it happened. Just heal the wound and bring this aspect into wholeness.
There really is no "time" as far as the soul is concerned. Everything is happening simultaneously which makes our multidimensional soul a parallel experience. Everything is energy or frequency. These shifts we are having are all about attuning the body, mind, and soul to the original blueprint for functioning as a light being in divine human form.
Light is coming to the earth now to assist with this shift because barriers or force fields that once prevented us from receiving the light needed to open all 12 strands of DNA. Those who are here as light workers are codes carriers--we hold blueprint material in our soul's frequency that we are emitting and anchoring in the earth and universe. This is broadcasted through light language songs, words, symbol writing, dancing, gesturing, and other artistic renderings we are creating as we are awakening.
-- Yvonne Perry
Learn more about the ascension process in Shifting into Purer Consciousness ~ Integrating Spiritual Transformation with the Human Experience. Yvonne Perry is available as a spiritual coach. See http://www.weare1inspirit.com/services for information about a free 15-minute evaluation to see if coaching is right for you.