Thanks for your immediate response.
Actual scope of PDF file is to open in a browser, allow user to make few data changes and save the modified PDF file in remote system (either File System or database). In this case user may keep a copy in local machine, but internally system has to version the changes everytime when user modifies the PDF file. The persisted version of pdf files from the remote location also published to the users for periodic changes...then the workflow starts from line 1 again...