You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: Please help me in changing my existing reservation, as my trip got postponed.

ASSISTANT: Sure, may I know your name.

USER: Ok, my name is Kenneth Smith.

ASSISTANT: Sorry to say, no reservation found with your name.

USER: That's ok, thank you for the response.

ASSISTANT: Thanks for reaching us.