You can make changes to the scene, re-render the passes, and immediately view the updated re-combination through the Render Target.

In this example, the camera direction is changed and the passes are re-rendered. When you switch to the Render Target in your Render View, a re-combination of the updated render passes appear.

1. Make a change to your scene, for example, change the camera angle.
   
2. In the Render View window, unlock the button .

   Now, when you render the render target, all passes and layers that are upstream of the render target (in other words, those feeding images to the render target) are re-rendered, and the compositing graph then updated.

3. In the Render View window, select Render Target > renderTarget1.
4. Click .

   The Render View shows a re-combination of the updated render passes.