Texas Estates Code - EST § 256.103. Procedure When Application for Probate Is Filed After Letters of Administration Have Been Granted

(a) A lawful will of a decedent that is discovered after letters of administration have been granted on the decedent's estate may be proved in the manner provided for the proof of wills.

(b) The court shall allow an executor named in a will described by Subsection (a) who is not disqualified to qualify and accept as executor.  The court shall revoke the previously granted letters of administration.

(c) If an executor is not named in a will described by Subsection (a), or if the executor named is disqualified or dead, renounces the executorship, fails or is unable to accept and qualify before the 21st day after the date of the probate of the will, or fails to present the will for probate before the 31st day after the discovery of the will, the court, as in other cases, shall grant an administration with the will annexed of the testator's estate.

(d) An act performed by the first administrator before the executor described by Subsection (b) or the administrator with the will annexed described by Subsection (c) qualifies is as valid as if no will had been discovered.