Places like this ask about your dietary restrictions during either the reservation or before the beginning of service. The chef will make on the fly adjustments

Places like this ask about your dietary restrictions during either the reservation or before the beginning of service. The chef will make on the fly adjustments based on each diner's needs. My brother and I went to Eleven Madison Park back in 2016 and mentioned my allergies ahead of time. Not only did they plan alternatives for me, they even included them in the printed out menu that they give to each diner as they leave as a memento of the meal.