Indiana Code Title 6. Taxation § 6-1.1-3-20

Sec. 20. If an assessing official changes a valuation made by a person on the person's personal property return or adds personal property and its value to a return, the assessing official shall, by mail, immediately give the person notice of the action taken.  However, if a taxpayer lists property on the taxpayer's return but does not place a value on the property, a notice of the action of an assessing official in placing a value on the property is not required.