Reference: Fataawa al-Hajj wal-‘Umrah – Page 45
Question: If the pilgrim arrives in Makkah and performs ‘umrah and [thereafter] relieves himself from the state of ihraam and remains in Makkah, when is he [then] required to assume the state of ihraam for the hajj, and from where?
Response: At any time after sunrise, he is required to assume the state of ihraam for the hajj on the day of tarwiyyah – which is the 8th day of Dhul-Hijjah, [that being] from the place where he is [currently] residing. He should then proceed to Minaa and perform there the Zhuhr, ‘Asr, Maghrib, ‘Ishaa and Fajr prayers.