All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Standing in the obligatory prayer is a pillar of the prayer that is not waived except if the person is physically unable to do it. If he can stand in part of the prayer and sit in part of it, then he should stand and only sit when he feels difficulty in standing. The Shaafi‘i scholar Al-Bujayrimi wrote, “If he cannot stand while reciting the Faatihah and the following soorah, he may sit after reciting the Faatihah and recite the soorah while sitting. He is not required to end it (the soorah) abruptly if he had already started reciting it in order to bow. If he can stand after reciting it in order to bow, he should do so; otherwise, he should bow from the sitting position.” [Haashiyat Al-Bujayrimi ‘ala Tuhfat Al-Habeeb]
Accordingly, you are required to repeat these two prayers.
Allah knows best.