Rather than clearing all answers from the survey, (which you can learn how to do here,) you can delete individual participant's responses, including your own.
First, go to your project and select the Participants tab.
From the Participants tab, scroll past the Map Overview and Referral Traffic Sources until you see the Participants section.
Find the participant whose dat you'd like to delete and click the x comment icon in the far right column of the participant's row to remove all responses from that individual.
Note: Deleted participant data and responses are stored for Federal Regulatory Compliance, but will be removed from project results & data.