"Act as chair" is a common term used to describe the person leading a meeting or discussion. There are many synonyms that can be used to replace this phrase, depending on the context of the situation. One synonym could be "preside over," which implies a sense of authority or control. Another option could be "moderate," which suggests a neutral and fair approach to managing the discussion. Alternatively, "facilitate" emphasizes the idea that the leader is helping the group work together effectively, while "direct" implies a more active role in guiding the conversation. Overall, there are many ways to describe the person in charge of a meeting, and choosing the right synonym can make all the difference in setting the tone and achieving positive outcomes.