IRS Form 8862, Information To Claim Certain Refundable Credits After Disallowance, is used if your earned income credit (EIC) was reduced or disallowed in a previous year and you would like to claim the EIC on your current return.
If you were previously disallowed from taking the EIC, claiming the credit this year will result in your return being rejected with IRS error code IND-046. This rejection will instruct you to attach Form 8862 to your return and refile.