You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I guide you?

USER: Can you please help me in changing my existing reservation, as my exam got postponed.

ASSISTANT: Sure, may I know your name for checking?

USER: Sure, my name is Gregory Nelson.

ASSISTANT: Give me a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found under your name.

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

ASSISTANT: Thank you for reaching us.