Metanoia:

[A] change in one's way of life resulting from penitence or spiritual conversion: "what he demanded of people was metanoia, repentance, a complete change of heart."

Enantiodromia:

[T]he tendency of things to change into their opposites, especially as a supposed governing principle of natural cycles and of psychological development: "the remorseless enantiodromia between good luck and bad."