As requirements change, you can deactivate an active or pending job in the rendering queue, or reverse the process and restart jobs that are inactive.
When you deactivate a job, the servers assigned to the job either drop the frame they are rendering or finish writing the frame, depending on where they are in the rendering process. The next pending job becomes active and begins to render.
You can reactivate a suspended job, or a job that was submitted as Initially Suspended from the Network Job Assignment dialog.