The time to make any changes to your 2009 personal income tax return is coming to a close soon. April 15, 2013 is the last day you can amend your 2009 income tax return if you have discovered an error on it. (you may have a bit more time if you filed an extension in 2009)
Changes can be made by filing a form 1040X. Make sure you give an adequate description of the changes you made or the IRS may reject your amendment.