The spirit can disrupt the reality of a substance, and therefore modify its Umbral form, by performing a feat of Gnosis. The spirit could, for example, create a door in a wall, enabling the spirit to pass through. The difficulty of this feat depends on the extent of the attempted change and how interesting, sensible, and clever the action is. The degree of success determines how much change is actually accomplished.
Power Cost: 2 to 10, depending on extent of change.