It seems that when suspensions are changed, it's because of an appeal. I'm not sure if such a thing happened yet in Rice's case.
Regardless, Rice will have a chance to make his case, and if the NFL violated the CBA, Rice could prevail.
Given that suspensions change regularly we already know the language of the CBA allows it. Suspensions don’t just change because of appeal, sometimes Goodell gives time off for quality time on the lecture circuit preaching against their behavior.
They didn’t, and he won’t.