Tex. R. Civ. P. 267

As amended through February 20, 2024
Rule 267 - Witnesses Placed under Rule
(a) At the request of either party, in a civil case, the witnesses on both sides shall be sworn and removed out of the courtroom to some place where they cannot hear the testimony as delivered by any other witness in the cause. This is termed placing witnesses under the rule.
(b) This rule does not authorize exclusion of (1) a party who is a natural person or the spouse of such natural person, or (2) an officer or employee of a party that is not a natural person and who is designated as its representative by its attorney, or (3) a person whose presence is shown by a party to be essential to the presentation of the cause.
(c) If any party be absent, the court in its discretion may exempt from the rule a representative of such party.
(d) Witnesses, when placed under Rule 614 of the Texas Rules of Civil Evidence, shall be instructed by the court that they are not to converse with each other or with any other person about the case other than the attorneys in the case, except by permission of the court, and that they are not to read any report of or comment upon the testimony in the case while under the rule.
(e) Any witness or other person violating such instructions may be punished for contempt of court.

Tex. R. Civ. P. 267