If you want a special offer from Dish, just tell them you are going to cancel the service. I just canceled my service (I was not under contract) and I was immediately sent to retention department which quickly offered a significant discount, free channels, etc, if I signed a two year contract. I wasn't interested, but during the next week I was contacted at least another couple of times by Dish with deals and then when the boxes showed up to return the receivers there was another one on paper inside it. One of them said "we are willing to do almost anything to keep you".
So if you want a deal, this is all you need to do.
In my case, I went to an OTA and a Roku with Netflix. Replaces $115/month bill with $8.99, and there is more to watch.