Musannaf Ibn Abi Shayba 13:2663

Abu Bakr narrated to us, he said: Abu Usamah narrated to us, from Abd al-Rahman ibn Yazid ibn Jabir, from Makhul, that the Messenger of Allah (may Allah bless him and grant him peace) said: "Whichever man is granted a life-gift (umra), it belongs to him; he may do with it whatever he wishes."