Like how can you be aware that you are delusional? Surely the self awareness negates the impact of the delusion as you see through the thoughts?

I once heard someone tell me that a schizophrenic who's delusional cannot simply be talked out of the delusions. So if they're told they are delusional and shown it, or they come to the awareness of that on their own, then surely they're no longer delusional?

Doesn't being delusional involve a complete lack of awareness of the fact that you are and just a complete defensiveness whenever anyone calls you out as if the others are attacking that absolute truth in your mind?