Sayyiduna Ibn Umar (may Allah be pleased with them both) used to say regarding a male or female slave who is jointly owned by several partners, and one of them frees his share, that it becomes obligatory to free the entire slave, if the person who freed his share possesses enough wealth to cover the value (of the remaining shares). The fair value will be assessed from his wealth, he will return the shares to the other partners, and the one who is freed will have his way made completely free. Abdullah bin Umar (may Allah be pleased with them both) narrated this from the Prophet (peace and blessings be upon him).