Ind. Code § 6-1.1-9-1

Sec. 1. If a township assessor (if any), county assessor, or county property tax assessment board of appeals believes that any taxable tangible property has been omitted from or undervalued on the assessment rolls or the tax duplicate for any year or years, the official or board shall give written notice under IC 6-1.1-3-20 or IC 6-1.1-4-22 of the assessment or increase in assessment. The notice shall contain a general description of the property and a statement describing the taxpayer's right to a review with the county property tax assessment board of appeals under IC 6-1.1-15-1.1.