Registration Question

Hi everyone,

I'm still new to Texas so this may be a stupid question. I had a car registered in my name here in Texas. The title that the bank has (car is not paid off) has only his name on the title as we just found out

Unfortunately he took the car when we split up and registration has been expired since July so he hasn't been able to drive the car. He wants to be able to register the car in his name only. How would we go about doing that since we don't have the title to the car?

Does he need to go to the tax office? Do I need to fill out anything so he can have it registered?