You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you today?

USER: Owing to an emergency, I want to change my existing reservation. Can you help me in that?

ASSISTANT: Sure, may I know your name?

USER: Patrick Williams.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, there are no active reservations on your name to cancel.

USER: Ok, thank you.

ASSISTANT: Thank you for reaching our service.