question #1 Sahih Muslim 1240d, Book 15, Hadith 220 : What is the significance of changing the intention from Hajj to ‘Umra during the days of Dhu’l-Hijja?

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.