So if I'm reading https://www.sos.state.tx.us/elections/laws/advisory2020-05.shtml correctly, it looks like everyone's party affiliation expired on December 31st going by:

If I have voted for one party in a prior calendar year, do I have to vote in the same party’s primary this year? No. A voter’s party affiliation ends at the end of each calendar year. Affiliation with a party in a prior year does not affect what primary an unaffiliated voter can vote in this year. (§162.010)

Is that understanding correct, or do the Texas Pedes need to do anything different to leave the Republican Party?