From Sahih Bukhari (Hadith 1085):
Narrated Ibn `Abbas:The Prophet (ﷺ) and his companions reached Mecca in the morning of the 4th Dhul-Hijja reciting Talbiya (O Allah! We are obedient to your orders, we respond to your call) ... intending to perform Hajj. The Prophet (ﷺ) ordered his companions to assume the Ihram for Umra instead of Hajj, excepting those who had Hadi (sacrifice) with them
Reference: Bukhari 1085