[Scripting Question] Making fire type attacks to make ice type pokemon to become water type

In my game, I want that if ice type pokemon is hit by a fire attack, he will become water type.
Can you help me to edit the script for that?
And, what do you think about this idea? I personally think it will make ice type stronger, because water type resist fire type and steel type.
Thank you!

That sounds complicated, but you could just have a specific fire move be a copy of the move "Soak", go from there and figure out how to limit it to only affecting Ice-type Pokemon