Therapist must form a personal relationship with the part first, before dealing with polarization
Putting the part in a room and looking at it through a window, begin further differentiating the Self from the other parts. Doesn't have to be a room, (if client can't grasp visual of room, could be due to trauma that happened in a room or closet). Can be a field, tank, desert, frozen tundra, etc. as long as there is some distance/separation.
How does the client feel toward the part in the room as the client looks at it through the window?
This is the key indication of differentiation