You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I guide you today?

USER: As my exam got postponed, I want to change my existing reservation. Can you help me out?

ASSISTANT: Sure, Wait for a minute. May I know your name please?

USER: Sure, my name is Edward Walker.

ASSISTANT: I am sorry to say that there is no reservation found.

USER: That's ok, thank you.

ASSISTANT: Thank you for reaching us.