Typically, only Data Managers, Tool Managers, Section Owners, and Administrators can update responses; however, if the Web Form has been enabled to allow users to update their own submissions, you will see an "Update" in the same row as your response in the Listing View. Data Managers and higher will see the "Update" link for all responses in the Listing View.

To update a response, click the "Fill Out" link in the Web Form listing. This will take you to the first page of the form.

Additionally, if you are viewing the details for a response and have access to update the response, you can click the "Update Response" link in the Utility Bar.