Aisha wanted to buy a slave-girl in order to manumit her. The girl's masters stipulated that her Wala' would be for them. Messenger of Allah ﷺ said (to ʿAisha), "What they stipulate should not stop you, for the Wala' is for the liberator."
قَالَ رَسُولُ اللَّهِ ﷺ لاَ يَمْنَعُكِ ذَلِكِ فَإِنَّمَا الْوَلاَءُ لِمَنْ أَعْتَقَ