You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Robert Lee.

ASSISTANT:  Robert Lee. How can I help you?

USER: I want to change my existing reservation due to bad weather condition, can you please help me with that?

ASSISTANT: Sure, can you give me a moment?

USER: Ok.

ASSISTANT: Sorry  Robert Lee, there is no reservation by your name.

USER: No problem, thank you.

ASSISTANT: Thank you for reaching us.