Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: The Messenger of Allah (peace and blessings be upon him) and his (peace and blessings be upon him) Companions arrived (in Makkah) on the morning of the fourth (of Dhu al-Hijjah), having entered ihram for Hajj. He (peace and blessings be upon him) ordered them to make it an Umrah, and this weighed very heavily on them. They said: "O Messenger of Allah! To what extent should we leave ihram?" He (peace and blessings be upon him) said: "Leave it completely."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10885