manumission

manumissio release Release from slavery or other legally sanctioned servitude; the giving of freedom; the act of manumitting.
1823, (w), The Pioneers, ch. 4:

The manumission of the slaves in New York has been gradual.

In the west, and especially in Cornwall, the names of the serfs were mainly Celtic,—Griffith, Modred, Riol, and so forth,—as may be seen from the list of manumissions preserved in a mass-book at St. Petroc's, or Padstow.

The more innocent dreamed of a manumission kindly bestowed by the new Emperor as one of a number of acts of justice and clemency proper to a new reign.

Rather than encouraging his countrymen to liberate their slaves, he opposed both private manumission and public emancipation.