Yoreh Deah Siman 267 Seif 64

 

סד הַמַּפְקִיר עַבְדּוֹ, יָצָא לְחֵרוּת וְצָרִיךְ גֵּט שִׁחְרוּר. וְאִם מֵת קֹדֶם שֶׁשִּׁחְרְרוֹ, הַיּוֹרֵשׁ כּוֹתֵב לוֹ גֵּט שִׁחְרוּר.

Seif 64

 

If someone declare his slave ownerless, the slave is granted his freedom. A bill of release is composed for him. If the master who declared him ownerless dies, his heir should compose the bill of release.