Texas Election Code - ELEC § 172.125. Additional Procedure for Accepting Voters in Runoff

(a) For a runoff primary election, the voter registrar shall make appropriate notations to indicate the preceding party primary for which the voter was accepted for voting, if any.

(b) An election officer at a runoff primary election polling place shall determine whether the name of a voter offering to vote is noted on the list as having been accepted for voting in another party's primary.  If the voter's name is so noted, the voter may not be accepted for voting at the runoff unless the voter executes an affidavit stating that the voter did not vote in the primary or participate in a convention of another party during the same voting year.