Cancel accidental Siri activation How do I tell Siri to go away when I activate it by accident?

The best I can come up with is "Cancel", which works but replies that "there's nothing to cancel". Functional, but irritating.

Searching on Google has thus far just turned up a whole lot of stuff about how to turn Siri off altogether, which isn't what I'm after.
Other than pressing the home button or sleep button, you can say a list of words:


Goodbye
Bye
See you
So long
See you soon/later