Tex. R. Civ. P. 63
As amended through February 20, 2024
Parties may amend their pleadings, respond to pleadings on file of other parties, file suggestions of death and make representative parties, and file such other pleas as they may desire by filing such pleas with the clerk at such time as not to operate as a surprise to the opposite party; provided, that any pleadings, responses or pleas offered for filing within seven days of the date of trial or thereafter, or after such time as may be ordered by the judge under Rule 166, shall be filed only after leave of the judge is obtained, which leave shall be granted by the judge unless there is a showing that such filing will operate as a surprise to the opposite party.
Tex. R. Civ. P. 63