You don't give enough information.If the change is significant and to gross proceeds, the IRS will pick up on this so it might be in your best interests to file a 1040x.However, if the change is minor and will result in minor change change to tax liability the hassle to amend may not be worth it.Occasionally the IRS computers will have some logic and not send out a tax bill for a $10 change in tax liability. However, sometimes the computer will send a demand notice for a $.50 liability.