What I was trying to say with my previous response was that the initial act of putting faith in God is an act necessarily performed by the believer. This is the act I was primarily referring to that would be the act 'undone'.
Though I suppose it begs the question. If one puts aside 'rebirth' and 'baptism by the Spirit', is one not in a sense undoing these acts? For now I am content with answering one doesn't necessarily have to undo these acts, I'll leave it at that.