Changing "OK Google" command in car android unit

[mystvean]

Hi, 

 

I have a generic android head unit in the car and a Samsung note 9. The android head unit is not android auto and is a stand alone unit. When I say "ok Google", for navigation, both devices respond which is annoying. When I use voice command to make a call, the phone will dial and the head unit will access the phone through Bluetooth and dial the phone number. It becomes more annoying when other people/devices in the car. Every device wants to navigate. I think the solution is to rename the car trigger commands to somethings else. Any easy method to change the voixe trigger command but still retain the the Google handling the voice recognition?