It is advisable for sure to amend your 1040 that you filed on Aril 15 or September 15 if you realize that some information is received after you filed your return or you come across some income or expense you missed to report. One of the major reasons for amending & reporting the correct amount can be explained with an example: like if in an year your received a Form 1099 from a contractor etc, the contractor must have submitted one copy of 1099 to the IRS, so if you are not reporting form 1099 income & IRS has a record of that, you are in trouble & be ready for an audit which in a way might attract interest & penalties, as the case may be. Even when you have meticulously filed your tax returns, there is no guarantee that you won't be filing revised one.

You can revise your IRS return by filing a tax amendment. Fill out forms and the necessary schedules and attachments. But remember, amended tax returns cannot be electronically filed, so you have to file them on paper.

Here are some points about filing amendment:

- Amended tax returns are generally filed if you need to correct things like total income, filing status, tax deductions, claimed dependents, or tax credits. You don't file amended returns to correct the mathematical mistakes in your tax numbers. That is done by the IRS.                         

 -Amending a tax return is a two-part process. The first part is that you have to fill out a new Form 1040. The second part is reporting the difference between the original tax return and the new one on the IRS Form 1040X. But please remember that usually the IRS inspects amended returns more carefully than the original returns. So, try to make your amended tax return with extreme accuracy.                                                                                                                                      

–The format of Form 1040X is that the original and amended Form 1040 are shown side by side.  Form 1040X has three columns, with Column A for reporting items from the original tax return, Column B shows the difference between the old and the new figures & Column C reports the items from the revised 1040. Extremely important part of Form 1040X is it’s  Part II, where you report specifically what changes you made to Form 1040, and the reason why you made those changes.