If your account has more than one survey container, you can easily copy a survey to reuse it for a new survey.

Go to the Surveys link at the top of your account, select Create a new survey, and select the Copy tab -- from there, you can select your survey and make a copy of it -- this will copy the survey structure to a new survey container. The responses and participant data is not copied, and the survey will be in design mode (not activated), so you can modify the structure.