Texas Election Code - ELEC § 172.059. Withdrawal from Runoff Primary

(a) A candidate for nomination may not withdraw from the runoff primary election after 5 p.m. of the 3rd day after the state canvass under Section 172.120.

(b) A withdrawal request for the runoff primary must be filed with the state chair, for a statewide or district office, or with the county chair, for a county or precinct office.

(c) If a runoff candidate withdraws, the remaining candidate is the nominee and the runoff election for that office is not held.