At any time after the entering of the order finding the missing individual to be dead, the probate court shall issue letters of administration or letters testamentary or an order granting year's support or an order that no administration is necessary in conformity with all of the requirements of the appropriate laws of this state on the estate of the missing individual and such letters or order, unless revoked, and all acts done in pursuance thereof and in reliance on such letters or order shall be as valid as if the missing individual were known to be dead.