If you wish to replace an old document without loosing the history and the statistics you have collected including document leads, please follow the following process:
Login to your account
Visit the document you want to replace
Select "Upload Revised Doc" tab
Click Browse and select the new document file from your computer
Make sure the file is displayed on the space provided.
If not try selecting it again.
Click "Upload Revised Document" tab
It will display "The flash page is under processing. Please wait."
Refresh the screen after about a minute.
It should now display the newly revised document (in both Flash and HTML5 formats to suit your browser needs)
Do consider sharing the document by selecting some of the social networks from the right hand side bar to inform your colleagues.