If the IRS has assessed additional tax from an audit and that liability remains unpaid, you can ask the IRS to reexamine the assessment through audit reconsideration. This request is for a liability that has already been assessed, and it is appropriate when you have new or previously unavailable evidence, missed the original audit correspondence, or can point to an IRS processing or computation error. It is not a response to a still-unassessed CP2000 proposal, and it is not a way to extend a Tax Court petition deadline. A request by itself does not automatically stop collection, reopen a court deadline, or guarantee that the assessment will be reversed. The organization checklist below is a practical aid; the IRS instructions govern the request.

Build the Evidence Packet

Start with the examination report and Form 4549, which show how the auditor reached the assessed amount. Identify each disputed item individually, then assemble a packet that pairs every disputed item with a supporting copy and a short written explanation of why the item is wrong or incomplete. New or previously unavailable documentation is the strongest foundation for a reconsideration request, so organize the packet around what has changed or what the auditor did not see. Publication 3598, the IRS audit reconsideration publication, is a useful reference for what to include. A complete packet generally covers the disputed items, the supporting documents, and a clear explanation of the error or new evidence, all prepared as a practical workflow rather than a required IRS format.

Form 12661, Disputed Issue Verification, may help you structure the request, but no special form is required to submit a reconsideration. The packet should be sent to the IRS office that handled the audit under current official instructions, not to an unrelated Appeals office. Keep copies of everything you send and retain proof of delivery. The IRS correspondence-examination page recommends the IRS Document Upload Tool at irs.gov/examreply as one route, or mailing to the office that handled the audit; mailing is not the only route. The full process is described on the IRS audit reconsideration page, and Publication 3598 provides the supporting guidance.

Know What Blocks Reconsideration

Not every assessed liability can be reopened. Final court determinations and specified binding agreements, such as a Form 906 closing agreement, a compromise agreement, or a Form 870-AD, can bar reconsideration. This does not mean that every form you signed in the past blocks a request, so review the specific agreement that applies to your case before filing. If the tax has been fully paid, use the applicable refund-claim process rather than the unpaid-assessment reconsideration route. For a fully paid individual income-tax assessment, Form 1040-X is generally the refund claim form, not Form 843, which cannot be used to refund or abate the underlying income tax itself. The Taxpayer Advocate Service explains how these options differ when you disagree with an assessment.

Separate Collection From Reconsideration

A reconsideration request does not automatically stop collection activity, and Publication 3598 states that collection may be delayed after documents arrive but not automatically. Verify the account status and any outstanding collection actions separately from the reconsideration request. If an installment agreement is in place, those payments must continue while the request is pending. Do not promise completion within any fixed number of days: the IRS publication includes a communication target, but that target is not a final resolution date. If collection is the immediate pressure, the reconsideration request is one track and a separate collection appeal is another, and they should be handled as distinct actions.

Decision Table: Choosing the Right Route

Situation Appropriate route
Audit assessed unpaid tax; new evidence or processing error exists Audit reconsideration with evidence packet
Tax already fully paid; individual income tax Check the refund-claim process and its deadline; do not use Form 843 for the underlying income tax
Still-unassessed CP2000 proposal Respond to the CP2000 rather than requesting postassessment reconsideration
Statutory notice of deficiency received Protect the separate Tax Court petition deadline

If a qualifying collection notice has also arrived, separately check Form 12153 for CDP or equivalent hearings and Form 9423 for CAP requests. These procedures review collection actions under their own requirements and do not replace reconsideration of the audit assessment.

Submission Checklist

What evidence qualifies for reconsideration?

New or previously unavailable documentation, missed audit correspondence, and IRS processing or computation errors are the recognized grounds. The request reviews an already assessed liability, so the evidence must relate to items in the examination report.

Does a reconsideration request stop collection?

No. Publication 3598 states that collection may be delayed after documents arrive but not automatically. Verify the account and any active collection actions separately, and continue installment-agreement payments while the request is pending.

How long does reconsideration take?

There is no guaranteed timeline. The IRS publication includes a communication target, but that target is not a final resolution date, and the request itself does not reopen a Tax Court deadline or guarantee reversal.

For tax firms

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