This chapter is from the book
Cancelling Siri
If you ever need to stop whatever Siri is doing, just say “Cancel” and then either tap the microphone button or press the Home button.
Because Siri remembers your ongoing thread of conversation, you might need to reset your current conversation at times. Say “Start over” or “Restart” to begin a new dialogue. Siri responds with a response such as, “Okay, Erica, what’s next?” or “What can I help you with?”