What does a costume designer do during the performance?

During a performance, a costume designer's primary role is to ensure that the costumes are functioning as intended, meaning they fit correctly, are comfortable for the actors, and align with the overall vision of the production. They may also be on hand to make quick adjustments or repairs if needed, helping to maintain the visual continuity of the characters. Additionally, they may collaborate with the director and stage management to address any costume-related concerns that arise during the show.