Sahih Bukhari Volume 5, Book 59, Hadith Number 679.

Narrated By Ibn Juraij : ‘Ata’ said, “Ibn ‘Abbas said, ‘If he (i.e. the one intending to perform ‘Umra) has performed the Tawaf around the Ka’ba, his Ihram is considered to have finished.’ said, ‘What proof does Ibn ‘Abbas has as to this saying?” ‘Ata’ said, “(The proof is taken) from the Statement of Allah: “And afterwards they are brought For sacrifice unto Ancient House (Ka’ba at Mecca)” (22.33) and from the order of the Prophet to his companions to finish their Ihram during Hajjat-ul-Wada.” I said (to ‘Ata’), “That (i.e. finishing the Ihram) was after coming from ‘Arafat.” ‘Ata’ said, “Ibn ‘Abbas used to allow it before going to ‘Arafat (after finishing the ‘Umra) and after coming from it (i.e. after performing the Hajj).”