Keep trying to contact the right person. It will be a violation of your probation to even leave the state of Texas without first getting permission. You got a good deal to get your DWI reduced. Don't screw it up by breaking a rule of probation.
Call the probation office back and ask to speak to a supervisor. You might also talk to your probation officer in Houston and see if he or she might have better luck getting through to someone. Finally, try again with your Houston probation officer. While your probation is out of Dallas, you are being supervised by the probation officer in Houston and he or she should have the authority to approve you going out of the country. I agree that you really need to take care of this before leaving the country.
The above advice is right. That said, I know how difficult it can be to get through to the court's probation officers at times. They're overwhelmed with files and not always willing/able to answer the phone. If i were you, I would call my attorney- you obviously had one to get that great result- and ask them who the new PO in the court is or how to handle this. Good luck
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