Ok, if you are close to your eligible upgrade. If you go to an indirect VZW store or a corporate VZW store, more than likely they will say no. If you want to make any headway, you need to call Customer Service from your phone *611 or 800-922-0204 and be POLITE and tell them your phone is on it's last leg and it would be very helpful if you could have the upgrade eligibility changed now. If they agree to this, you will have to upgrade over the phone and not in a local VZW store.
This is the best angle to get your upgrade earlier. I had to get my tissues out a lot when I worked in a VZW call center, and if it was a good paying customer and not hard to get along with, I usually honored it earlier than the upgrade date. However, it went through manager exception, so I'd place the order, even though your actual upgrade date was not changed, and the manager would approve it. This is why when people say they called VZW and they said they'd all an upgrade now then go to the local store they'd look at their screen and say "sorry, we can't honor an early upgrade".