Musnad Ahmad 1167:41

Ubaydah ibn Humayd narrated to us, from Yazid ibn Abi Ziyad, from Mujahid, from Asma bint Abi Bakr, who said: "We performed Hajj with the Messenger of Allah (peace and blessings of Allah be upon him), and he commanded us, so we turned it into an Umrah. We then exited the state of Ihram completely, until the incense burners were wafting between the women and the men."