There is a pause, but it doesn't let you save, quit and come back. Also, it doesn't even seem to let go of the CPU and Memory, or if it does, it takes to long to be useful. When I pause, I want to get my CPU back to do other things.
It may be similar to cancel. I used to think cancel didn't work, but now I think you just have to go away for 30 minutes and hope it is done canceling when you come back.