While completing your survey, you can use the progress bar or the arrows on your keyboard to navigate to questions you've already answered or skipped, and revise or even remove your answer.
If you've already submitted your survey but the survey round is still open, you can reset your survey to remove your answers. When resetting your survey, all your answers from that survey round disappear instantly so we only recommend doing this if you feel very strongly about removing your responses.
After resetting your survey, you can then either complete the survey again or leave it as it is. Only you can reset and edit your own survey answers; it's not possible for an administrator to do this on behalf of an employee.
It's not possible to reset a survey after your company has hard-closed the survey round. See How do I reset my survey answers? for different ways to reset your survey.