You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you?

USER: I am Justin Walker, want to alter my recent reservation due to some emergency. Please help me out with that.

ASSISTANT: Let me check your reservation status in our records, please wait for a while.

USER: Sure, please wait for a while.

ASSISTANT: Sorry to inform that, no reservation is found with your criteria.

USER: It's ok, thank you.

ASSISTANT: Thank you very much for approaching us.