Tex. R. Civ. P. 162
At any time before the plaintiff has introduced all of his evidence other than rebuttal evidence, the plaintiff may dismiss a case, or take a non-suit, which shall be entered in the minutes. Notice of the dismissal or non-suit shall be served in accordance with Rule 21a on any party who has answered or has been served with process without necessity of court order.
Any dismissal pursuant to this rule shall not prejudice the right of an adverse party to be heard on a pending claim for affirmative relief or excuse the payment of all costs taxed by the clerk. A dismissal under this rule shall have no effect on any motion for sanctions, attorney's fees or other costs, pending at the time of dismissal, as determined by the court. Any dismissal pursuant to this rule which terminates the case shall authorize the clerk to tax court costs against dismissing party unless otherwise ordered by the court.
Tex. R. Civ. P. 162