Melting is not a chemical change. Melting is a physical change. Physical changes are reversible. Chemical changes are not. If a substance is melted, freezing returns the original substance.
Ice is melted to give water. Water is frozen to give ice. These are reversible physical changes.
In physical changes, the molecules are unaltered except for the amount of energy which they possess.
Chemical changes alter the composition of the molecules.These changes are not reversed easily. In chemical changes, bonds break, atoms rearrange and different bonds form. An example of a chemical change is the reaction of iron with oxygen to form rust.