the sacrificial animals, whether he is performing single Hajj (ifrād) or qirān.

The three imams—Abū Ḥanīfah, Mālik, and al-Shāfiʿī—and the great majority of scholars therefore held that such dissolution is not prescribed.
Imām Aḥmad, his disciples, the hadith scholars, and the Ẓāhirīs, however, judged the dissolution to be permissible.

The majority support their view with the report narrated by Abū Dāwūd (1542) from Abū Dharr: “That concession was granted only to the party who were with the Messenger of Allah ﷺ,” and with the narration recorded by Aḥmad (15292) from Bilāl ibn al-Ḥārith, who said, “I asked, Messenger of Allah, is the conversion of Hajj into ʿUmrah for us alone or for all people?” He replied, “For us alone.”
They contend that this ḥadīth abrogates the earlier narrations on dissolution, in which the Prophet ﷺ instructed the Companions to break the pre-Islamic custom that forbade ʿUmrah during the months of Hajj. Such is the evidence advanced by the majority.

Those who affirm the permissibility of dissolution, on the other hand, cite eighteen sound and excellent ḥadīths transmitted by more than a dozen learned Companions, all of them explicit in allowing a pilgrim who has not brought the sacrificial animals to convert his Hajj into an ʿUmrah. Hence, when Salamah ibn Shabīb said to Imām Aḥmad, “Abū ʿAbd Allāh, everything you say is fine and beautiful—except that you approve of dissolving Hajj,” Aḥmad replied, “I had credited you with intelligence. I possess eighteen sound and excellent ḥadīths, all concerning the dissolution of Hajj—am I to abandon them for your opinion?”

Among those ḥadīths is the report recorded by Muslim (1247) from Abū Saʿīd al-Khudrī: “We set out with the Messenger of Allah ﷺ loudly proclaiming Hajj. When we reached Mecca he ordered us to make it an ʿUmrah, except for anyone who had driven the sacrificial animals. Then, on the Day of Tarwiyah, after we had set out for Mina, we entered into ihram once again for Hajj.”
Another is what Muslim (1236) likewise relates from Asmāʾ bint Abī Bakr, who said: “We left in a state of ihram, and the Messenger of Allah ﷺ said, ‘Whoever has with him a sacrificial animal should remain in ihram…’”