When Felix is replaced, Paul’s case is before Festus. The Jewish leaders wanted Festus to call Paul to Jerusalem for the trial, so that they could murder him in an ambush along the way. The Jews offered many accusations which they could not prove.
Paul is happy to speak before Agrippa. First, because he is pleased to have the evidence of his case examined closely by the highest officials, but also because he is pleased to preach the gospel to him!