This article is a Stub.
The reappearance of a headmate can be shocking, disconcerting, or evoke suspicion and examination from the other system mates.
Sometimes they are exactly the same, having had a vacation or respite, or gone on some unknown adventure and being none the worse for the wear.
And other times, most of the time, they come back changed in some way. Aged up, evolved, generally more "whole" or transformed in some way that is generally eventually seen as a positive change. They may have acquired more traits, more self-acceptance, self-esteem, a more solid presence, etc.
Like the proverbial caterpillar who enters a chrysalis, the resident has become something different, while all their former "Self" is still there.
This does not mean that the rest of the system is ok with this. Pain of separation, abandonment, fear of absolute death, mourning, having let them go, come to terms with it, changed their life situation due to that person no longer being present, etc. can be factors in the readjustment to a returned headmate. Or even survivor guilt, for any who were glad that they were gone, wished them dead, or who felt it should have been "them instead." Some may even be disappointed or angry with the person having come back — angry they left in the first place, or disappointed in them as a person for having left, through being disappointed they reappeared or angry that they're back.
A resident reappearance certainly can create a lot of inner turmoil and a period of readjustment for a multiple system.