Edit multiple book marks (all book marks) in a single go.
Batch editing bookmarks
i found this on http://www.tek-tips.com/viewthread.cfm?qid=1651836
1) open file and display bookmarks (in Acrobat 9 in this case)
2) select all bookmarks (blue bars displayed)
3) point to any bar, right click, select 'Properties'
4) in 'Bookmark Properties' select 'Actions' then select 'Add..' (caveat: NOT EDIT or you'll wind up with all bookmarks pointing to the same page)
5) after pressing 'Add...' you'll see a 'Menu Item' pop-up, which about midway down the list has an entry for 'View>Zoom>Fit Page'. Select that and press 'OK'. Then hit 'OK' one last time and you're done.
6) check bookmarks
I found this useful after combining .pdf-s. One sidenote: if the bookmarks have sub-bookmarks they you'll have to display them all to make the change universal. Otherwise, you'll find that only those immediately visible are changed. 