The Gemara discusses the language used for freeing an eved C'nanani. Isn't it forbidden to do so?
y barach, brooklyn ny
While you are correct that it is generally forbidden to do so, we see that sometimes it is permitted. The most famous example of this is the story of Rebbi Eliezer (Gitin 38b) who freed his Eved Kenani in order complete a Minyan for Davening.
[In any event, whether it is forbidden or not, our Gemara is discussing what terminology is able to free the slave.]
All the best,