The Prophet ﷺ said, "Whoever frees his share, or a portion, of a jointly owned slave must complete the slave's emancipation from his own wealth if he has the means. If he does not, the slave is to be valued fairly, and the slave shall be allowed to work to earn the remainder of his price without being burdened beyond his capacity."
أن النبي ﷺ قال: من أعتق نصيبا، أو شقيصا في مملوك فخلاصه عليه في ماله إن كان له مال، وإلا قوم عليه، فاستسعي به غير مشقوق عليه.
Bukhari related it in the Book of Emancipation (2527), and Muslim in the Book of Emancipation (1503:3), both through the route of Saeed bin Abu Aruba, from Qatada, from Nadr bin Anas, from Bashir bin Nuhayk, from Abu Hurairah, who narrated it.The meaning is that the slave is not freed from the second partner's share if the first partner is wealthy, but rather the first person who freed his share is given the choice between freeing the second share himself, or having the slave work to earn his own release.His saying, "a portion," means part of him.This contains evidence for Abu Hanifa, for the second partner has the choice, if he wishes he frees his share, and if he wishes he lets the slave work to earn half his value, with the right of patronage shared between the two of them.