Ind. Code § 6-1.1-12-36

Sec. 36. (a) A person who receives a deduction provided under section 26 (before its expiration), 29 (before its expiration), 33 (before its expiration), 34 (before its expiration), or 38 (before its expiration) of this chapter for a particular year and who remains eligible for the deduction for the following year is not required to file a statement to apply for the deduction for the following year.

(b) A person who receives a deduction provided under section 26 (before its expiration), 29 (before its expiration), 33 (before its expiration), 34 (before its expiration), or 38 (before its expiration) of this chapter for a particular year and who becomes ineligible for the deduction for the following year shall notify the auditor of the county in which the real property or mobile home for which the person received the deduction is located of the person's ineligibility before March 31 of the year for which the person becomes ineligible.

(c) The auditor of each county shall, in a particular year, apply a deduction provided under section 26 (before its expiration), 29 (before its expiration), 33 (before its expiration), 34 (before its expiration), or 38 (before its expiration) of this chapter to each person who received the deduction in the preceding year unless the auditor determines that the person is no longer eligible for the deduction.