After about 1642 in N.A., some enslaved people were given their "half-freedom." They were free to work on their own, as long as their master did not require their services. When he needed them, they returned to work for him.
Both slaves and those with half-freedom were paid by their masters for their work. It was the law. But the children of those with half-freedom were not free.
In 1644, eleven slaves petitioned the DWIC for their freedom and it was granted. These men and their wives were given farmland in return for payment of an annual quitrent. They would also be required to serve the DWI when needed but would be paid for their labor. Interestingly, the children of these eleven would remain DWIC slaves. Slaves were not given complete liberty, however. Former slaves had to pay a yearly tax, and their children remained slaves; historians now call this “half freedom.”
"Legally speaking, the slaves in New Netherland had a right of ownership, which was inconceivable in many other colonies.....The most notable legislation that was favorable to slaves and free blacks, as compared to the position in other colonies, had to do with the administration of justice. The testimony of slaves was declared valid in law, and slaves were allowed to institute legal proceedings against others, whether slave or free....." New Amsterdam, New York by Martine Gosselink p 216