Sahih Bukhari Volume 3, Book 47, Hadith 2504

حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا جُوَيْرِيَةُ بْنُ أَسْمَاءَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ ـ رضى الله عنهما ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏"‏ مَنْ أَعْتَقَ شِرْكًا لَهُ فِي مَمْلُوكٍ وَجَبَ عَلَيْهِ أَنْ يُعْتِقَ كُلَّهُ، إِنْ كَانَ لَهُ مَالٌ قَدْرَ ثَمَنِهِ يُقَامُ قِيمَةَ عَدْلٍ وَيُعْطَى شُرَكَاؤُهُ حِصَّتَهُمْ وَيُخَلَّى سَبِيلُ الْمُعْتَقِ ‏"‏‏

Narrated By Ibn 'Umar : The Prophet said, "Whoever manumits his share o a jointly possessed slave, it is imperative on him to manumit the slave completely if he has sufficient money to pay the rest of its price which is to be estimated justly. He should pay his partners their shares and release him (the freed one).