The Sanford Police Chief, as I recall, disagreed publicly with Serino, the Lead Detective.
The Chief did not, as I recall, block Serino from filing a Manslaughter affidavit with Sanford prosecutors.
No one can make the officer change the charge, but you also have other investigators on scene that night that would have agreed to with Sorino. You had investigators from ths State Attorneys office as well as Florida Dept. of Law Enforcement. Remember no one charges or arrest unless the prosecutors say so. At the time the report is file they have still not gotten all the facts. Would you want to be lead investigator and decide at that time not to charge before you have everything? I would not.