system
Given the following post, respond as if you're commenting on Reddit:
human
If I take ice II at 500MPa and -80°C, and reduce the pressure to 100kPa, will the ice reorganise itself into ice I? Does it need to be melted in order to transition between its solid phases?

Do any of the solid phases of ice form a stable configuration that can be taken out of its usual temperature-pressure boundaries once formed?
gpt
I don't know about ice specifically, but for other materials, phase changes between different solid phases certainly does take place. For example the changes between the different phases in steel is used in order to create the desired microstructure to give the desired bulk physical properties for particular applications of steel.