You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I guide you at this moment?

USER: Owing to an emergency, my meeting with client got postponed. So I wan you to change my existing reservation.

ASSISTANT: Sure, I am here to help you with this. Can you please provide your name to check your reservation status?

USER: Sure, Stephen Davis here.

ASSISTANT: Wait a moment please.

USER: Sure.

ASSISTANT: Stephen Davis, there is no active reservation found under your name in our database.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Thank you for contacting us.