core-bundle/src/Resources/contao/library/Contao/Model.php
public function detach($blnKeepClone=true)
	{
		$registry = Registry::getInstance();

		if (!$registry->isRegistered($this))
		{
			return;
		}

		$registry->unregister($this);

		if ($blnKeepClone)
		{
			$this->cloneOriginal()->attach();
		}
	}
public function detach($blnKeepClone=true)
	{
		$registry = Registry::getInstance();

		if (!$registry->isRegistered($this))
		{
			return;
		}

		$registry->unregister($this);

		if ($blnKeepClone)
		{
			$this->cloneOriginal()->attach();
		}
	}
Detach the model from the registry

@param boolean $blnKeepClone Keeps a clone of the model in the registry