The Electric Reliability Council of Texas (ERCOT) does it for you. When you sign up for a plan with a new provider, ERCOT will send you a mailer confirming the switch. You have three days upon receiving the mailer to change your mind. If you don't, you'll have a new provider within seven days, and ERCOT will notify your old provider. Just remember, if you abandon a contract before it's complete, you will be on the hook for any fees or penalties detailed in its Terms of Service.
The PUC’s mission is to protect customers, foster competition, and promote high-quality infrastructure. In addition to regulating the states electric utilities and implementing legislation, the PUC offers Texas residents assistance in resolving consumer complaints. If you have a complaint with your electricity company you can go to the official PUC website and file an informal complaint.