How interconversion in matters can be achieved?
Interconversion between the various states of matter is usually achieved by change in temperature. That is, solids can be converted into liquids by heating. Similarly liquids can be converted into gases by heating. Conversely, gases can be converted into liquids and liquids can be converted into solids by cooling. In gases which are highly compressible, change in pressure also brings about a change in state of matter.
Hence, we can say that states of matter can be interconverted by
1) Change in temperature
2) Change in pressure