Yes, the phase changes of water, such as melting (solid to liquid) and boiling (liquid to vapor), represent reversible processes and can reach a state of dynamic equilibrium under the right conditions. When water is in a closed system, these phase changes occur in a way that the rates of the forward and reverse processes balance each other.
For example, when water is heated to the point of melting (0°C under standard pressure), ice (solid water) melts to become liquid water. However, as the liquid water is cooled, the process can reverse, and the liquid will freeze back into solid water. This process is reversible because the phase change can occur in both directions under suitable conditions, and the equilibrium between solid and liquid water can be established.
Similarly, when water is heated to its boiling point (100°C at standard atmospheric pressure), liquid water changes to steam (vapor). In a closed system, steam molecules can condense back into liquid water, as water molecules at the surface of the liquid escape into the gas phase and molecules in the gas phase return to the liquid state. This is an example of a reversible equilibrium between liquid and vapor. The point at which the rate of evaporation (liquid to gas) equals the rate of condensation (gas to liquid) defines the equilibrium position of the system.
The equilibrium states for both melting/freezing and boiling/condensation are characterized by a constant temperature and pressure at which the opposing processes occur at equal rates. In systems where water is under constant temperature and pressure conditions, these phase changes are indeed reversible, and a dynamic equilibrium is established.