If anyone emancipates a share in his slave, he should completely emancipate him if he has money; but if he has none, then slave will be required to work (to pay for his freedom), but he must not be overburdened. (Using translation from Abū Dāʾūd 3937)
أَنَّ رَسُولَ اللهِ ﷺ قَالَ «مَنْ أَعْتَقَ شِقْصًا لَهُ مِنْ عَبْدٍ فَإِنَّ عَلَيْهِ أَنْ يُعْتِقَ بَقِيَّتَهُ إِنْ كَانَ لَهُ مَالٌ وَإِلَّا اسْتَسْعَى الْعَبْدُ غَيْرَ مَشْقُوقٍ عَلَيْهِ»