Can a team take the court with only 4 players netball?

This is being asked as we have one set of parents upset with a game that was played to get in the grand finial, there was one girl that had two halfs off, as she is the weakest player and we want to win, ( we won the game which means we are in the grandfinal) but I am concerned that her parents are going to take there 2 kids out and another player which is the reserve which leaves us with 5 players From a concerned assistant coach