Tex. Tax Code § 33.56

(a) If, in a suit to collect a delinquent tax, a court renders a judgment for foreclosure of a tax lien on behalf of a taxing unit, any taxing unit that was a party to the judgment may file a petition to vacate the judgment on one or more of the following grounds:

(1) failure to join a person needed for just adjudication under the Texas Rules of Civil Procedure, including a taxing unit required to be joined under Section 33.44(a);

(2) failure to serve a person needed for just adjudication under the Texas Rules of Civil Procedure, including a taxing unit required to be joined under Section 33.44(a);

(3) failure of the judgment to adequately describe the property that is the subject of the suit; or

(4) that the property described in the judgment was subject to multiple appraisals for the tax years included in the judgment.

(b) The taxing unit must file the petition under the same cause number as the delinquent tax suit and in the same court.

(c) The taxing unit may not file a petition if a tax sale of the property has occurred unless:

(1) the tax sale has been vacated by an order of a court;

(2) the property was bid off to a taxing unit under Section 34.01(j) and has not been resold; or

(3) the tax sale or resale purchaser, or the purchaser's heirs, successors, or assigns, consents to the petition.

(d) Consent of the purchaser to a petition may be shown by:

(1) a written memorandum signed by the purchaser and filed with the court;

(2) the purchaser's joinder in the taxing unit's petition;

(3) a statement of the purchaser made in open court on the record in a hearing on the petition; or

(4) the purchaser's signature of approval to an agreed order to grant the petition.

(e) A copy of the petition must be served in a manner authorized by Rule 21a, Texas Rules of Civil Procedure, on each party to the delinquent tax suit.

(f) If the court grants the petition, the court shall enter an order providing that:

(1) the judgment, any tax sale based on that judgment, and any subsequent resale are vacated;

(2) any applicable tax deed or applicable resale deed is canceled;

(3) the delinquent tax suit is revived; and

(4) except in a case in which judgment is vacated under Subsection (a)(4), the taxes, penalties, interest, and attorney's fees and costs, and the liens that secure each of those items, are reinstated.