It was narrated from Aishah that :The Prophet (ﷺ) used to pray when he was sitting. He would recite while sitting, then when there were thirty or forty verses left, he would stand up and recite while standing, then he bowed and prostrated, then he would do likewise in the second rak'ah.
أَخْبَرَنَا مُحَمَّدُ بْنُ سَلَمَةَ، قَالَ حَدَّثَنَا ابْنُ الْقَاسِمِ، عَنْ مَالِكٍ، قَالَ حَدَّثَنِي عَبْدُ اللَّهِ بْنُ يَزِيدَ، وَأَبُو النَّضْرِ، عَنْ أَبِي سَلَمَةَ، عَنْ عَائِشَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يُصَلِّي وَهُوَ جَالِسٌ فَيَقْرَأُ وَهُوَ جَالِسٌ فَإِذَا بَقِيَ مِنْ قِرَاءَتِهِ قَدْرُ مَا يَكُونُ ثَلاَثِينَ أَوْ أَرْبَعِينَ آيَةً قَامَ فَقَرَأَ وَهُوَ قَائِمٌ ثُمَّ رَكَعَ ثُمَّ سَجَدَ ثُمَّ يَفْعَلُ فِي الرَّكْعَةِ الثَّانِيَةِ مِثْلَ ذَلِكَ .
Nesai
The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day • Hadith 1648