Survey

Hi - I've created a survey using the single answer response allowing me to create a customized survey that registrants must complete to register for our event. We would like to add an additional question to learn a bit more about where registrants are from. It appears that Zoom will not allow me to add a question now that people have registered and completed the survey. Does anyone know if it's too late for me to edit the survey, or if there is a way to still do so?