macbook pro display settings not configurable

I was experimenting with resolution and refresh rate for my extension monitor and now many of my display settings options are missing, such as mirroring, refresh rate, etc. How can I get them back? The extension monitor is not connected to the the laptop, now. Going back to default would be fine. Thanks

Are you saying that:

1. Settings which normally appear in the Displays preference pane are not there for a second monitor but are for the other screen.
2. The monitor is not connected at the moment?

If so, connect the extension (external) monitor again and the settings should reappear. Those settings are only present if an external monitor is connected.