If your vehicle is in the clearing (CLR) State, it means that even though you are currently busy with a job, you are close to the drop-off point and will soon be ready to receive a new job. You can press on a button in the driver app in order to signal that you are available to take new jobs.
Once you are close enough to the destination, the CLR button will appear *. Press on this button to activate it and it will turn red. The vehicle is now considered to be in the CLR state.