A pilgrim has three options regarding ihram for Hajj, based on the different types of Hajj. In ifrad, the pilgrim enters into ihram for Hajj and then takes it off after finishing. In tamattu`, he or she can enter into ihram for `Umrah, then go out of ihram after finishing the rituals of `Umrah and enjoy everything that was prohibited during ihram. Then the pilgrim enters into ihram again for Hajj and takes it off when finished. In qiran, the pilgrim enters ihram for both Hajj and `Umrah and remains in that state until the rituals of both `Umrah and Hajj are completed.
Tackling the issue in point, here is the fatwa issued by Sheikh `Adil Salahi, a London-based Islamic scholar:
“There is no discrepancy in the matter. When the Prophet (peace and blessings be upon him) arrived in Makkah and did the Tawaf on arrival, he told his Companions to complete their `Umrah and release themselves from ihram. They wondered at that and questioned him, specially as they saw that he himself did not do what he told them to do. He explained that he had brought his hadi (sacrificial animal) with him. Anyone who did that could not change his intention from doing Hajj to doing `Umrah alone. Otherwise, that is permissible for people who had not brought their sacrificial animals with them. Doing the `Umrah first was recommended by the Prophet himself (peace and blessings be upon him).”