is::reScheduleTask

public function reScheduleTask(array $newData)
{
	$task = $this->taskPool[$this->taskId];

	// do not deal with tasks with no created date
	if((string) $task['CREATED_DATE'] == '')
	{
		return array();
	}

	if(isset($newData['MATCH_WORK_TIME']))
	{
		$task->setMatchWorkTime($newData['MATCH_WORK_TIME'] == 'Y');
	}

	// define end date...
	if((string) $task['END_DATE_PLAN'] == '')
	{
		if((string) $newData['END_DATE_PLAN'] != '')
		{
			$task->setEndDatePlan(new DateTime($newData['END_DATE_PLAN']));
		}
		else
		{
			$task->setEndDatePlanUserTimeGmt($this->calendar->getEndOfCurrentDayGmt()->toStringGmt());
		}
	}

	// must keep previous values of task; we`ll need it on relcalculating related task`s lags further
	$this->taskOriginDates = array(
		'START_DATE_PLAN' => $task->getStartDatePlanGmt(true),
		'END_DATE_PLAN' => $task->getEndDatePlanGmt(),
	);

	// $startDate and $endDate are dates that were changed, not just actual dates!
	$startDate = null;
	$endDate = null;

	if($newData['MATCH_WORK_TIME'] == 'Y')
	{
		// MATCH_WORK_TIME was set to Y, we have to reschedule and re-check existing dates even if no actual date change required
		$startDate = 	isset($newData['START_DATE_PLAN']) ? $newData['START_DATE_PLAN'] : $task['START_DATE_PLAN'];
		$endDate = 		isset($newData['END_DATE_PLAN']) ? $newData['END_DATE_PLAN'] : $task['END_DATE_PLAN'];
	}
	else
	{
		// MATCH_WORK_TIME is set to N or even left unchanged, we just take what we have in $newData (if we have smth)
		if(isset($newData['START_DATE_PLAN']))
		{
			$startDate = $newData['START_DATE_PLAN'];
		}
		if(isset($newData['END_DATE_PLAN']))
		{
			$endDate = $newData['END_DATE_PLAN'];
		}
	}

	// we need ensure we deal with DateTime objects in $startDate and $endDate, not strings or smth else
	$startDate = 	$this->castToDateTimeGmt($startDate);
	$endDate = 		$this->castToDateTimeGmt($endDate);

	if($startDate || $endDate) // smth were changed, do job
	{
		/*
		// we had no end date, but we get it in $newData.
		if($endDate && !$task['END_DATE_PLAN'])
		{
			$task->setEndDatePlanUserTimeGmt($endDate->toStringGmt());
		}
		if(!$endDate && !$task['END_DATE_PLAN']) // no data to shift
		{
			return static::makeTaskReturnStruct($task);
		}
		*/



		if($startDate && $endDate) // both changed => shift
		{
			$task->setStartDatePlanUserTimeGmt($startDate->toStringGmt());
			$task->setEndDatePlanUserTimeGmt($endDate->toStringGmt());

			$duration = $task->calculateDuration();
			$this->matchWorkingTime($this->taskId, $startDate, $endDate, $duration);
		}
		elseif($startDate) // start changed => resize to left
		{
			$task->setStartDatePlanUserTimeGmt($startDate->toStringGmt());

			$this->matchWorkingTime($this->taskId, $startDate);
		}
		elseif($endDate) // end changed => resize to right
		{
			$task->setEndDatePlanUserTimeGmt($endDate->toStringGmt());

			$this->matchWorkingTime($this->taskId, null, $endDate);
		}
	}

	return static::makeTaskReturnStruct($task, $newData);
}