/**
  * @return ExistingReservationSeries
  */
 public function Build()
 {
     $this->series->WithId($this->id);
     $this->series->WithCurrentInstance($this->currentInstance);
     $this->series->WithRepeatOptions($this->repeatOptions);
     foreach ($this->instances as $reservation) {
         $this->series->WithInstance($reservation);
     }
     foreach ($this->events as $event) {
         $this->series->AddEvent($event);
     }
     $this->series->WithPrimaryResource($this->resource);
     $this->series->Update(1, $this->resource, 'title', 'description', $this->bookedBy);
     return $this->series;
 }