To change the name of a form, visit your Form Editor (if you’re in the My Forms section, select the form that you want to rename and click on the first option – Edit). After you’ve opened the editor, spot the form name – it is placed at page top, right below the main menu and right above the form builder wizard. Click on the form name, delete the old name and type in the new one.
A more faster way would be to go to My Forms, select the form and click on the link Rename, located on the right. A lightbox will open where you can change the name of the form and hit Save to exit.