That's a tough one.. because what is the conceptualisation of personality?

The answer wrt "what parts" would differ based on which collection of alledged parts we decide to chose from; there's many different theories and measurement of indicators that are suggested to make up the whole of the concept that is named 'personality'.. there is no standardised uniform list.

The answer on how much it would change, to my knowledge, would differ immensely based on the age you are when discovering that, since after around a certain age (~25 if i remember correctly) your personality pattern is ripened/v robust to changes.