In Hegel you have essentially two actors encountering one another and each is a subject, but in order to be a full subject, each needs to be recognized by the other. Each affirms the other as a subject in its own right that is simultaneously equal and different from me. If both people can affirm that, then you have a reciprocal egalitarian, symmetrical process of recognition. But, famously, in the master-slave dialectic, they encounter one another on highly asymmetrical, unequal terms, terms of domination or subordination. Then you get non-reciprocal recognition.