Missouri Revised Statutes Title XXXI. Trusts and Estates of Decedents and Persons Under Disability § 474.410. Revocation of subsequent will also revokes first will--exception

1. If a second will, which, had it remained effective at death, would have revoked the first will in whole or in part, is thereafter revoked by acts under section 474.400, the first will is revoked in whole or in part, unless it is evident from the circumstances of the revocation of the second will or from testator's contemporary or subsequent declarations that he intended the first will to take effect as executed.

2. If a second will, which, had it remained effective at death, would have revoked the first will in whole or in part, is thereafter revoked by a third will, the first will is revoked in whole or in part, except to the extent it appears from the terms of the third will that the testator intended the first will to take effect.