可以用子数据更改父函数的实现吗？

I was wondering is it ok to change implementation of parent class with child class data. I have situation of creating a child class (form) witch extends parent class (other form with same elements). If I dont change implementation of parent class some html Elements will have same id and both forms are on same page. So i am not sure is this legitimate way in terms of OOP rules. I was wondering why to inherit parent class when i want to change it?!

public function __construct(AddTaskErrors $addTaskErrors=null,
childData = []) 
{
$this->addTaskErrors = $addTaskErrors;
$this->childData = $childData;

}    
public function build(array $predefinedValues = [])
{//name id label value  type za input
    //input
    $addTask = (isset($this->childData[self::ADD_TASK])) ? $this->childData[self::ADD_TASK] : self::ADD_TASK ;
    $this->addElement(new InputTextElement(
            $addTask , 
            $addTask , 
            $addTask , 
            '', 'text', $predefinedValues));

    $addTaskDeadline = (isset($this->childData[self::ADD_TASK_DEADLINE])) ? $this->childData[self::ADD_TASK_DEADLINE] : self::ADD_TASK_DEADLINE ;
    $this->addElement(new InputTextElement(
            $addTaskDeadline, 
            $addTaskDeadline, 
            $addTaskDeadline, 
            '', 'text', $predefinedValues));

    //select
    $addTaskPriority = (isset($this->childData[self::ADD_TASK_PRIORITY])) ? $this->childData[self::ADD_TASK_PRIORITY] : self::ADD_TASK_PRIORITY ;
    $this->addElement(new SelectElement(
            $addTaskPriority, 
            $addTaskPriority, 
            $addTaskPriority, 
            PriorityType::createFromDefaultValue(), $predefinedValues ));

    return $this->getElements();
}