Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: The Messenger of Allah (peace and blessings be upon him) said: "This ‘Umrah from which we have benefited, whoever does not have a sacrificial animal should come out of ihram (i.e., end the state of consecration); everything becomes lawful for him. And ‘Umrah has been incorporated into Hajj until the Day of Resurrection."
Hadith Referenceسنن دارمي / من كتاب المناسك / 1894