You dont give enough information.If the change is significant and to gross proceeds the IRS will pick up onthis 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 taxliability the hassle to amend may not be worth it.Occasionally the IRS computers will have some logic and not send out a taxbill for a 10 change in tax liability. However sometimes the computer willsend a demand notice for a .50 liability.