Indiana Code Title 29. Probate § 29-1-5-6

Sec. 6.  No will in writing, nor any part thereof, except as in this article provided, shall be revoked, unless the testator, or some other person in his presence and by his direction, with intent to revoke, shall destroy or mutilate the same;  or such testator shall execute other writing for that purpose, signed, subscribed and attested as required in section 3 or 3.1 of this chapter.  A will can be revoked in part only by the execution of a writing as herein provided.  And if, after the making of any will, the testator shall execute a second, a revocation of the second shall not revive the first will, unless it shall appear by the terms of such revocation to have been his intent to revive it, or, unless, after such revocation, he shall duly republish the previous will.