You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I best aid you now?

USER: I am Helen Campbell. Owing to an emergency, I want to change an existing reservation. Please help me in changing the reservation?

ASSISTANT: Sure, that's what I am here. Please wait a moment.

USER: Sure.

ASSISTANT: Thanks for being waiting. Unfortunately, there is no active reservation found on your name.

USER: Not an issue.

ASSISTANT: Thanks for approaching us.

USER: Thank you.