Well, wait right there. Instead of asking for a break outright, consider switching your story. Let's consider a hypothetical situation in which you've booked a room (that you know it is still refundable) but you would rather stay at a smaller hotel with higher posted rates. When calling this location, let them know that you have a cheaper rate at a different resort, but that you'll book with them if you can get a discounted price, free night, or even an upgrade. Independent hotels and local chains can often offer more flexibility since they get hit harder with the recession and feel more of a pressure to fill rooms.
Get one more tip when you read more.
Another call I've made is to a boutique hotel I had been dying to stay at — and offered to book (and pay for) my trip in full, in advance. They matched the lowest rate at the larger chain probably because there was a guarantee I wouldn't cancel 48-hours beforehand, and then I waited 'til I arrived to let the true bargaining begin.