Rule 3.340 Effect of Sustaining Challenge

When a juror is challenged and the challenge is approved, that juror is removed from the case and cannot serve on the jury.

There are two ways this can happen. A "challenge for cause" means there is a specific reason the juror cannot be fair, like knowing one of the parties. A "peremptory challenge" means a lawyer removes a juror without giving any reason at all. Either way, the result is the same: the juror is excused and plays no part in the trial.