JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
You can create a copy or duplicate a form by following this guide: http://www.jotform.com/help/27-How-to-clone-an-existing-form-from-your-account. You can then edit or update the cloned form while the original one is still being used.
Do let us know if that's what you are looking for.