Once an "Active" survey moves to "Completed", besides viewing the results report, three actions can be taken: "Reactivate it", "Clone it", and/or "Preview" the questions that make it up.
Reactivate Survey
No matter the reason you need to reactivate a survey, doing so is very simple. You need to go to "Completed Surveys", select the survey you wish to activate, and set a new expiration date."
Clone
You can also clone it, copying the survey and allowing you to edit whatever you want from it.
Preview
The preview generates a view of the survey (in read-only mode) with the questions and answer options, just as the users received them.