OK, that might be the right solution for your problem, but it is not the right solution for your question.
Because actually your survey was not deactived, but expired, if you could solve it as described. Getting an expired survey back to life is easy and it is just changing or deleting the expiration date.
Now if the survey would be deactived, then Tony's solution would be the one. Which is of course more complicated and only possible if nothing in the survey has been changed.
Help us to help you!
Provide your LS version and where it is installed (own server, uni/employer, SaaS hosting, etc.).
Always provide a LSS file (not LSQ or LSG).
Note: I answer at this forum in my spare time, I'm not a LimeSurvey GmbH employee.