Texas Property Code - PROP § 28.0091. Unsigned Change Order

(1) the contractor or subcontractor has not received a written, fully executed change order for the owner-directed additional work;  and

(2) the aggregate actual or anticipated value of the additional work plus any previous owner-directed additional work for which the contractor or subcontractor has not received a written, fully executed change order exceeds 10 percent of the contractor's or subcontractor's original contract amount.