Ordinarily, a presumption of revocation arises when a testator had possession of a will and that, after the testator’s death, the will could not be found after a diligent search. This presumption, however, is rebuttable. If the heirs or beneficiaries of the will can prove that the missing will was properly executed, its contents, its loss or destruction, and that it was not revoked by the testator, then the probate court may honor the missing will.
Obviously, secondary evidence is going to be needed if the will has gone missing; as such, conclusive proof will need to be proffered to establish its existence and contents. To accomplish this, witnesses, the author or attorney of the will, and beneficiary may testify to its contents and that it was lost or destroyed in a manner that does not suggest that the testator intended to revoke the will.
This is very difficult to accomplish. More often than not, then, it is usually the case that the attorney who drafted the will possesses a copy or a photocopy of all of the portions of the will. From there, a hearing is set to determine its validity. All interested parties are permitted to attend.
Once it is offered, however, it is still subject to will challenges under RSMo 473.083.