If you already paid for Sunday ticket, suspending or cancelling is just throwing money away since you can't recoup that loss.
If you don't pay for ticket, you can suspend your account for up to 6 months, at which point it gets automatically reactivated. If you cancel, you they prorate the bill so the sooner you cancel the more they will refund you. I used to suspend my account every summer because I didn't watch much TV in the summer. However when I moved DirecTV couldn't get a signal through the treeline that is conveniently on my neighbors property edge so I was forced to switch to Time Warner, which is like having to eat reconstituted yak shit after years of eating at Lonestar's. When I cancelled, I had to send back the DVR, but I got refunded the prorated portion of my bill, which was all but 3 days worth.