Disasters happen.

Imagine you have finished a 900-page PDF document and you realize that the left margin shouldve been 0.5 inches smaller. Oops!

No cause for fear and trembling though. Its actually very easy to take care of this vexing problem if you own a copy of the Acrobat Professional, or the writer version of the Acrobat as opposed to the freely downloadable reader version.

Open your mis-formatted PDF document in Acrobat Professional and follow these steps:

1) Select Document > Crop Pages from the main menu to display the Crop Pages dialog box.

2) Select the LEFT margin and enter 0.5 by making sure that the Unit is in inches.

3) Select ALL for the Page Range.

4) Click OK, and you are done.

You can also select to change only a certain range of pages by entering the page Numbers in the From and To fields.

You can further specify if you want those changes only in ODD or EVEN numbered pages (within the specified range) by selecting the appropriate option from the APPLY TO drop-down list.

You can always cancel your margin changes by clicking the Set to Zero button.

And by selecting the Constrain Proportions check-box you can adjust all 4 margins simultaneously, by the same amount.