You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Eric Lewis.

ASSISTANT: How may I assist you at this moment?

USER: I want to change my existing reservation, can you please help?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please give me a moment to check your previous reservation status.

USER: Sure.

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

USER: No problem, thank you.

ASSISTANT: Thank you for reaching us.