Musannaf Ibn Abi Shayba 13:3146

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Ibn Abi Khalid narrated to us, from ‘Amir, that he was asked about a woman who had manumitted a slave of hers for a period of months, and the woman died before that. ‘Amir said to her sister: "He is your slave; if you wish, you may take possession of him, and if you wish, you may leave him."