Aspecting
This is sometimes called "faceted".
Aspects, what we used to call "Heavily Aspected" in the good ol' days — if you think of a person as a 6-sided die, they have different "faces" or aspects they can show to the world, but they're always the same person. the same basic beliefs, religion, or "Soul stuff". They're not an independent POV (point of view). They have only 1 point of view at a time, but they may switch to any of their various "faces" and have a different POV in various situations. But only 1 at a given time.
Singular folk can be heavily aspected too. A very different "them" but always it's "just them" at the same time. Work mode vs. Home mode. or Superbowl Person vs. Mowing the Lawn Person. There can be extremely stark differences, but they really are "the same person" inside — just wildly variant wrapped around their same person-ness.
Heavily aspected folk are welcome to identify as plural — there's a grey area between heavily aspected vs. being a median system. They likely would not identify as "multiple" per se, but plurality is a much larger umbrella and they have "many aspects" and thus may determine whether they would like to be under the plural umbrella — if their many-ness feels like it fits under that identity.
Some people, while not technically multiples, still display some of the characteristics in the form of "aspecting." These people exhibit distinct outward personality shifts, perspective shifts, etc. without experiencing a difference in memory retention, a sense of being a different person, or a loss of self-perspective.
Thus someone can have different ways to act in different situations without technically being a separate person. [However, if shifts include memory difficulties, or feelings of not being in control of your actions when you're doing something (a feeling that you're watching or feeling your body doing things YOU are not controlling) then this probably isn't the answer to the shifts in your personality.]
"Past Life aspecting" - someone who defines aspects along lines of separate lives (ie: "aspecting along past life lines" or "past-life aspect")
"Form aspecting" - someone who defines aspects along lines of separate physical forms/races