public Person retrieve() {
        if (personArray.length == 0) {
            return null;
        }
        Person result = personArray[0];
        for (int position = 0; position < personArray.length-1; position++) {
            if (personArray[position+1] != null) {
                personArray[position] = personArray[position+1];
                personArray[position].setPosition(personArray[position].getPosition()-1);
            }
        }
        queueSize--;
        
        if (isHalfSize()) {
            halveArraySize();
        }
        
        return result;
    }