By mastering samyama, prajna the light of awareness dawns; and insight, the light of higher consciousness comes; the vision, that is wisdom arises.
Dharana, dhyana and samadhi -- are internal compared to the five that precede them viz., yama, niyama, asana, pranayama and prathyahara.
Change is the very nature of the functioning of gunas the qualities. When gunas the qualities are functioning, a change takes place.