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.
Solid to liquid - it is freezing.
Liquid to solid - melting.
Liquid to gas - evaporation.
Gas to liquid - condensation.
Solid to gas - sublimation.
The process that causes changes of the Earth's continents over time is called "Plate Tectonics."
In order to know what two changes of state are involved in a process one needs to know what the process is.
temperature
The number of protons in the nucleus changes
condensation =)
melting
Matter changes state because of temperature and pressure. These quantities bring change.
Boiling
Addition or removal of heat energy.
Sublimation is the process in which solid directly changes into gaseous state. In the case of changing gas into solid, the process is known as deposition.
Evaporation is the process where a liquid state changes from its LIQUID state to a GAS state.
In evaporation, a liquid such as water changes to a gaseous state. In sublimation, a solid such as ice changes driectly to a gas or vapor without going through a liquid state.