On January 28, 2022, we notified the Director, Return Integrity and Compliance Services, of our concerns with the reconciliation process when there are undelivered checks. This concern arises when the taxpayer files their Tax Year 2021 tax return but has a check for an advance Child Tax Credit payment that was returned undelivered after the taxpayer filed their tax return. In these situations, the taxpayer will not receive the payment from the undelivered check and will need to work with the IRS, after filing their tax return, to recover their payment. We recommended that the IRS develop a process to continue to proactively identify and correct accounts with undelivered advance Child Tax Credit that post to accounts after the IRS processes the Tax Year 2021 tax return.