You are describing Personas. They don't have to be limited time, but they are still who they are. Changelings only have one personality, their own. They just have far more developed Personas than others naturally would.

But again you're ignoring the issue the commenter had with this. That people would do these changes at random and act like a completely different person in an attempt to be the center of attention. Changelings don't do this. They aren't Davis the Spellsword that becomes Alice the town bicycle when they smell cinnamon. They would choose one and stay in it until they saw a need to switch.

Changelings also don't live as several different people. Depending on what they need to do, or the culture of that group of Changelings, they'll have a couple personas they use the most. It may be for a job or something else, but it isn't a personality. It's an act they put on so people will treat them as just another person and not an evil Doppelganger.

Persona and Personality are not the same thing.