The change from liquid to gas at the surface of a liquid is known as vaporization.
Decreasing the temperature a liquid become a solid.
In a word, temperature. A physical change will change the matter's state based on it's temperature. For example, water, H2O. You can increase the temperature to 212oF and it will change state from a liquid to a gas. You can decrease the temperature to 32oF and it will change state from a liquid to a solid. To answer your question, the process of doing so would be increasing or decreasing temperature of matter.
Melting Point
melting point
Melting Point
Drop the temperature.
The heat of fusion is the amount of energy required to change 1 unit mass of a solid to a liquid at constant temperature.
Melting point.
The term defined as the temperature at which a substance changes from a solid to a liquid state is called the melting point.
Melting is the term defined as the process by which a substance changes state from solid to liquid.
Change the temperature or pressure or both, to change a substance from one state to another. (such as gas to liquid)