Transition between the Archetypes whose grounding is less physiological is pretty straightforward – it’s easy to move out of almost every Mortality Archetype, for example – but others require a lot more character sheet surgery and fictional wrangling to make sense.
How have you adjudicated Archetype switches in your own campaigns and one-shots?
It’s an audacious mechanic, and I’d love to see a more in-depth discussion of that in a future supplement.