Government employees who want to sue for such things as defamation have to let the state know before they file suit. It gets trickier, however, when the employee amends a previous suit.
Recent case: Brenda Ford worked for a school district and claimed she was disabled. The district suspended her after she was accused of distributing confidential information.
Ford filed an ADA lawsuit. Several months later, she sent a tort claim notice to the school district, letting it know she intended to file a defamation and emotional distress lawsuit, too. She then amended the original complaint.
Her employer said it was too late, since Indiana law says employees have to give notice before they sue. But the court allowed the amendment, reasoning it was like a new lawsuit. (Ford v. Gary Community School Corp., No. 2:07-CV-21, ND IN, 2008)