We can freeze water and it becomes ice. We can melt the ice and it becomes water. This is a physical change. The water and ice can go back to the thing it was.
Matter can change. We can bake a cake. The ingredients of a cake change from eggs, flour and butter to be a cake. This is a chemical change!
Matter can be a solid, a liquid or a gas.
Matter can freeze. Matter can melt. Matter can be heated to a gas! These are changes of state!