Here's a list of voice commands you can say to Siri to change settings in iOS 7.
1. Turn on airplane mode.
2. Is Bluetooth on?
3. Make the screen brighter.
4. Turn on Bluetooth.
5. Go to Twitter settings.
6. Show me my privacy settings.
7. Enable Wi-Fi.
8. Open Mail Settings.
9. Turn on Do Not Disturb.
If you want a much longer list that goes beyond just the settings app, start Siri and ask it this question:
"What can I ask you?"
You'll see a list of app categories. Just tap on the category to see a list of commands you can use with Siri for that app.
Siri does a lot more in iOS 7 so be sure to spend some time with it. You will probably find it a lot more useful than in previous versions of iOS.