The way peripeteia happens in the play is:
He expects to be vindicated, only to learn that he is guilty of both murder and incest.
Explanation:
Peripeteia is the concept of reversal in that there is change that is led by the very willingness to not change things in the way they are.
The Anagnorisis is the administering of the predestination over the attempt at establishing the free will by naive heroes of the play.
Oedipus believed that because of his actions he will be vindicated and that he has escaped the curse but all it does is mean that he is guilty of both murder and incest because of his very attempt to flee from his fate.