I said to the Prophet ﷺ, "Messenger of Allah, why have the people exited their state of ihram while you have not done so after your Umrah?"He replied, "I have matted my hair and garlanded my sacrificial animal, so I will not exit ihram until I complete the Hajj."
أخبرنا عبيد الله بن سعيد قال حدثنا يحيى عن عبيد الله قال أخبرني نافع عن عبد الله بن عمر عن أخته
قلت للنبي ﷺ يا رسول الله ما شأن الناس حلوا ولم تحل من عمرتك قال إني لبدت رأسي وقلدت هديي فلا أحل حتى أحل من الحج
Bukhari transmitted it in Hajj, chapter on twisting collars for camels and cattle, no. 1697, and Muslim in Hajj, chapter clarifying that one performing qiran does not exit the state of ihram except at the time the one performing Hajj alone exits it, no. 1229, from the hadith of Yahya bin Saeed Qattan, with the same chain, and it is in al-Kubra, no. 3662.