To edit question set in a survey, please follow these steps below:
Step 1: Under Surveys, pick a survey that you want to edit by clicking its name or click view survey, like the image below
Step 2: Under the Question Set tab, there are three categories, pick one. Then, choose a question set by clicking its name or click View Question Set
Step 3: Under Edit Survey Question Set for: Participant page, you can:
Edit name, response type, page header, and also add or remove the question.