As soon as contracts are exchanged, the transaction becomes legally binding. Before the exchange, there's no legal obligation to complete and it's possible for either party to withdraw from the deal without legal penalty. Once you exchange, you've formally committed to transfer legal ownership of the property.
State laws, rather than local county laws, dictate whether you are eligible to change your name, but you must initiate your civil suit by filing documents with the Bexar County District Clerk. The Civil Filing Main Line phone number is (210) 335-2621. The Bexar County District Clerk's Office is located at 101 W.