‘Abd Allah b. ‘Umar reported the Messenger of Allah (peace be upon him) as saying:
If anyone emancipates his share in slave, a fair price for the slave should be fixed, give his partners their shares, and the slave be thus emancipated. Otherwise he is emancipated to the extent of the share which he emancipated.
Sunan Abi Dawud, Book 31, Hadith 15