You tell only a minor part of the full story, so it's impossible to tell. All I can say is this:
1. If you saved the form to your hard disk before submitting it, it's still there and can be edited.
2. If you didn't save it, but used a browser (like Internet Explorer) to fill it, it might still be in the Temporary Internet Files. Go and search in My Computer.
I have a Form in PDF format I have done some mistakes when I fill-up it.
Now the new forms are not available on Net & also in Shops.
So can I Correct the Form where I Did Mistakes?