What is the Parent of a ViewController placed as SubView?

I have a ViewController where I have placed another ViewController on one of it's SubView. In that ViewController (placed in SubView) I need to go to another ViewController on a click event. But when I can self.navigationController pushViewController method , My log says It's pushed but Screen is not changing.

My attached image depicts the scene , Match Details is the host ViewController. White rectangle is a UIView , and the guest ViewController is placed within this white rectangular View. When I click on the round button (Click written) , then another ViewController should replace the Host ViewController.

It's a complex application , so pasting codes here should not be a good idea. Just a few explanation would help me a lot , I can fix the codes myself. Some some hint required about my mistake.

Thanks in advance for help.

When you add view of viewController as subview you need also register your viewController as child view controller for parentViewController.

Example:

UIViewController *mainVC = [UIViewController new];
UIViewController *childVC = [UIViewController new];

[mainVC addChildViewController:childVC];
[mainVC.view addSubview:childVC.view];

UIViewController *parentVC = childVC.parentViewController;

Here parentVC is mainVC.