The heading of the subpoena or commission must be "The Texas Department of Transportation." It must state the style of the case, that the case is pending before SOAH, the time and place at which the witness is required to appear, the party at whose insistence the witness is summoned, and the date of its issuance. It must be signed by the executive director, the department's general counsel, or an attorney in the department's office of general counsel. It must be addressed to any sheriff or constable of the State of Texas or other person authorized to serve subpoenas or commissions as provided in Rule 176.5, Texas Rules of Civil Procedure.