What kind of state changes does first frost involve?

Liquefaction and sublimation. From the physical point of view, dew in the Millennium is frost, and frost is liquefaction and sublimation in the change of material state respectively. In physics, the process of material changing from one state to another is called the change of material state. Things can be transformed into each other, and there are six state changes: melting, solidification, vaporization, liquefaction, sublimation and sublimation.