sentences: a phase change is when a substance changes from one state into another state
docs: thaw is phase_change. vaporization is phase_change. termination is change_of_state. nullification is change_of_state. phase is state_of_matter. change_of_state is change. vaporization is physical_state_change_event. soiling is change_of_state. transfer is change_of_state. phase_change is natural_process.