You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your name please?

USER: I am Gregory Thomas.

ASSISTANT: How can I help you Gregory?

USER: Can you please help me out to change my existing reservation?

ASSISTANT: Sure, please give me a minute.

USER: OK.

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

USER: OK, that's fine. Thank you for your help.

ASSISTANT: Thank you for reaching us.