You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I best support you today?

USER: I am Samuel Green. I want to change my existing reservation due to the change of my trip dates. Can you help me?

ASSISTANT: We are here to help you.

USER: Thank you.

ASSISTANT: Just give me a moment please.

USER: Sure.

ASSISTANT: Sorry to say that there is no reservation found on your name.

USER: No problem. Thank you for your response.

ASSISTANT: Thanks for connecting us, have a nice day.