If you have already created your Response Form, click on the Edit link next to the Response Form you wish to edit. Click the Preview link to view the Response Form to be sure you’re choosing the correct form.

If you have already begun to receive responses to your Response Form, you will not be able to edit the form; the edit link will not appear. If you need to make a change to the form, you'll have to copy the form by clicking the Clone link. Then you can make the changes to the newly cloned form. Remember that you'll be given a new url that you'll have to use to replace the old url of the form you corrected.