Self employed

You would have to edit the vehicle asset entry and indicate that you stopped using the vehicle for business:

Later, you would indicate that you started using the vehicle for personal purposes during the year:

This will stop depreciation on the old vehicle and remove it from your business. You would enter the new vehicle like you did the original one, that entry would not be affected by the removal of the original vehicle.

If you had taken a section 179 deduction on the vehicle, you would go to the Less Common Business Situations section and choose Sale of Business Property. Then check the recapture option box to enter your recapture information.