Michigan § 700.2509 - Revival of revoked will.

If a subsequent will that wholly revoked a previous will is later revoked by a revocatory act under section 2507(1)(b), the previous will remains revoked unless it is revived. The previous will is revived if it is evident from the circumstances of the revocation of the subsequent will or from the testator's contemporary or subsequent declarations that the testator intended the previous will to take effect as executed.

If a subsequent will that partly revoked a previous will is later revoked by a revocatory act under section 2507(1)(b), a revoked part of the previous will is revived unless it is evident from the circumstances of the revocation of the subsequent will or from the testator's contemporary or subsequent declarations that the testator did not intend the revoked part to take effect as executed.

If a subsequent will that revoked a previous will in whole or in part is later revoked by another, later will, the previous will remains revoked in whole or in part, unless it or its revoked part is revived. The previous will or its revoked part is revived to the extent it appears from the terms of the later will that the testator intended the previous will to take effect.