ENOfficial
Ibn 'Abbas (Allah be pleased with them) reported: Allah's Messenger (ﷺ) came along with his Companions when four days had passed out of ten days (of Dhu'l-Hijja) and they were pronouncing Talbiya for Hajj, and he (the Holy Prophet) commanded them to change (this Ihram) into that of 'Umra.
Source: sunnah.com
Other translations
Arabic
وَحَدَّثَنَا هَارُونُ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا مُحَمَّدُ بْنُ الْفَضْلِ السَّدُوسِيُّ، حَدَّثَنَا وُهَيْبٌ، أَخْبَرَنَا أَيُّوبُ، عَنْ أَبِي الْعَالِيَةِ الْبَرَّاءِ، عَنِ ابْنِ عَبَّاسٍ، - رضى الله عنهما - قَالَ قَدِمَ النَّبِيُّ صلى الله عليه وسلم وَأَصْحَابُهُ لأَرْبَعٍ خَلَوْنَ مِنَ الْعَشْرِ وَهُمْ يُلَبُّونَ بِالْحَجِّ فَأَمَرَهُمْ أَنْ يَجْعَلُوهَا عُمْرَةً .
sunnah.com