As I said, "Don't Jack with the Tenants -- Just Follow the Law"
If you're unsure of the law, you should consult an attorney. Sorry, I am not one, just a property manager.
You can find the relevant statutes on line in Texas Property Code, Title 4, Chapter 24 and TItle 8 Chapter 91-92. You should read 92.0081(b)(3) and (c) for the authority to change locks. It is quoted here:
(b) A landlord may not intentionally prevent a tenant from entering the leased premises except by judicial process unless the exclusion results from:
(1) bona fide repairs, construction, or an emergency;
(2) removing the contents of premises abandoned by a tenant; or
(3) changing the door locks on the door to the tenant's individual unit of a tenant who is delinquent in paying at least part of the rent.
(c) If a landlord or a landlord's agent changes the door lock of a tenant who is delinquent in paying rent, the landlord or the landlord's agent must place a written notice on the tenant's front door stating:
(1) an on-site location where the tenant may go 24 hours a day to obtain the new key or a telephone number that is answered 24 hours a day that the tenant may call to have a key delivered within two hours after calling the number;
(2) the fact that the landlord must provide the new key to the tenant at any hour, regardless of whether or not the tenant pays any of the delinquent rent; and
(3) the amount of rent and other charges for which the tenant is delinquent.
Since many aspects of the Property Code may apply to your situation, this extract should not be considered the entire story. Again, no one except an attorney can offer you advice on the law, which is why it is quoted without comment or interpretation, and the suggestion is always to consult an attorney.