I prayed Maghrib in congregation with the intention of making up 'Asr, then I remembered that I had already prayed 'Asr?

Question:
I say: Honorable Shaykh, may Allah grant you success, I forgot the 'Asr prayer, so the Maghrib adhan was called and I prayed it as the 'Asr prayer. In the second rak'ah, I remembered that I had already prayed 'Asr previously, so I changed it to the Maghrib prayer. What is the ruling on my prayer in...

Answer:
It is not valid, because it is not permissible to switch from one prayer to another during the prayer. The prayer you switched from is invalid, and the prayer you switched to is invalid. So you must repeat the prayer. Yes.