Taxpayers have certain rights in an audit. Upon conclusion of the audit, the IRS may accept the tax return as filed or propose adjustments to the return. The IRS may also assess penalties and interest. Generally, adjustments must be proposed within three years of the due date of the tax return. Certain circumstances extend this time limit, including substantial understatement of income and fraud. The taxpayer and the IRS may agree to allow the IRS additional time to conclude an audit. If the IRS proposes adjustments, the taxpayer may agree to the adjustment, appeal within the IRS, or seek judicial determination of the tax.