Sahih Muslim Book 7, Hadith Number 2787.

Chapter : Types of Ihram- It is permissible to enter into the state of Ihram singularly for the sake of Hajj or for tamattu’ bi’l-‘umra ila’l-Hajj or for both hajj and ‘umra together.

‘Aisha (Allah be pleased with her) reported that she put on Ihram for ,Umra and arrived ‘at Mecca) but did not circumambulate the House as she had entered in the period of menses, and then put on Ihram for Hajj and performed all the rituals concerning it (except circumambulating the House). The Apostle of Allah (may peace be upon him) said to her on the day of march (when pilgrims come to Mina): Your circumambulation would suffice both Hajj and Umra. She, however, felt reluctant. Thereupon the Holy Prophet (may peace be upon him) sent her with ‘Abd al-Rahman to Tan’im and she performed Umra (with separate rituals) after Hajj.