Maybe they are going after a another charge. He was found not guilty on 2nd degree. Depending on what the jury found him not guilty of, there may be room for another charge like manslaughter or negligent homicide.
No, specifically say ‘reinstate the charge’
A couple points, but basically that would still be double jeopardy.
Zimmerman was found not guilty of both Murder 2 and the necessarily included lesser offense of manslaughter.
Double jeopardy ostensibly covers all charges flowing from the same act or actions. The government can;t keep putting a person to trial on "lesser and lesser offenses" that flow from the same act. The exception right now is that the federal government will violate the constitution (and the judges think this is a nifty idea!) by charging with a separate federal crime (e.g., hate crime), if the state fails to obtain a conviction. That's how the police officers in the Rodney King incident were jailed. Tried twice for the same acts, but one trial was on a state offense by state prosecutors, the other was a federal offense tried by federal prosecutors.