That depends upon whether or not the judge dismisses "with prejudice". Since any manslaughter charge would be based on the same act, with the same set of facts as the original charge, that would result in him being prosecuted twice for substantially the same crime. If the charge is dismissed with prejudice, filing again under manslaughter would violate the prohibition against double jeopardy.
usually there is prosecutorial discretion. Don't know how it works in florida. Can the prosecutor withdraw the 2nd degree murder charge and re-file as manslaughter ? or do they first have to get the judge to dismiss ?
Thanks