If you wish to hide a vehicle from Stream you can set a disposal date for this vehicle which will hide it in your account.

In the Vehicle Details Menu, click on Edit or double click on the Vehicle to access Vehicle Details

Enter a Disposal Date.

If you ever want to bring this vehicle back into service you can use the Search button to find disposed vehicles and remove this date.

To add a replacement vehicle click Add and enter the required vehicle details, then click 

Save Vehicle.