Save signature on the current copy (not in a new copy)

I am opening the PDF document within my web application based on the availability of the Adobe Acrobat XI Pro on the client PC. The user want to sign the document using the freehand signature option. My problem that when the user add his signature and try to save the document, it always ask him to save a new version. Can I overcome this issue by any means? I need once he finish and click on save in the PDF, it will be saved on the same version.