Sahih Bukhari Volume 001, Book 006, Hadith Number 316.
Narated By 'Urwa : 'Aisha said, "We set out with the Prophet in his last Hajj. Some of us intended to perform 'Umra while others Hajj. When we reached Mecca, Allah's Apostle said, 'Those who had assumed the lhram for'Umra and had not brought the Hadi should finish his lhram and whoever had assumed the Ihram for 'Umra and brought the Hadi should not finish the Ihram till he has slaughtered his Hadi and whoever had assumed the lhram for Hajj should complete his Hajj." 'Aisha further said, "I got my periods (menses) and kept on menstruating till the day of 'Arafat, and I had assumed the Ihram for 'Umra only (Tamattu'). The Prophet ordered me to undo and comb my head hair and assume the lhram for Hajj only and leave the 'Umra. I did the same till I completed the Hajj. Then the Prophet sent 'Abdur Rahman bin Abi Bakr with me and ordered me to perform 'Umra from At-Tan'im in lieu of the missed 'Umra."