[deduce]

You won't be able to get the upgrade discount since the plan doesn't support it (they fixed the loophole where you use to) but you can access your My Sprint account page and switch the device there. You'll likely be charged the upgrade fee if the phone has never been previously activated. The only problem you might run into is if the HD7 Pro is 4G. I'm not sure if it'll force a plan change or just add on the Premium Data.