You can edit pdf documents by using Adobe Acrobat 9 software. You can use this software to work directly with pdf documents to imply minor changes. You can very easily apply or add text and you can also make changes to color, characters, word spacing, and the text size. Furthermore, with images and tables you can move or edit them. The main benefits of this software is that you can permit copy
. editors or printers to make changes on your behalf. Also files can be reused that needs only basic text changes. You can find more information here: http://www.adobe.com/products/acrobat/solutions/detail/edit_pdf.html