What is the ruling for someone who started reciting Surat Al-Fatihah silently, then remembered in the middle of it that it should be recited aloud; does he continue the recitation or restart?

Scholars have differed concerning one who recites Al-Fatiha silently and then remembers while reciting it [that it should be recited aloud]: Should he build upon what he has read, or repeat it?

The Malikis are of the view that he should restart, unless he has already bowed for rukoo'. The Hanbalis, according to the more sound opinion in their madhhab (definition), are of the view that he should build upon his recitation.

However, if he forgets to recite silently in a silent prayer and recites aloud, then remembers, he should build upon his recitation, according to a unanimous opinion.

It was reported from Ahmad that if one recites silently in a prayer where recitation should be loud, until he finishes Al-Fatiha, and then remembers, he should restart Al-Fatiha reciting aloud and perform the prostration of forgetfulness (sujood as-sahw).

Ibn Qudamah mentioned that regarding one who recites silently in a place of loud recitation, there are two narrations: either he continues his recitation, or he repeats his recitation by way of choice, not obligation.