Ind. Code § 6-1.1-14-7

Sec. 7. The county assessor, a township assessor (if any), or ten (10) or more taxpayers who are affected by an equalization order issued under section 5 of this chapter may file a petition for review of the order with the county auditor of the county to which the equalization order is issued. The petition must be filed within ten (10) days after notice of the order is given under section 9 of this chapter. The petition shall set forth, in the form and detail prescribed by the department of local government finance, the objections to the equalization order.