You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Alexander Lewis.

ASSISTANT: Can you please tell me how can I assist you?

USER: Please help me by changing my reservation to next week.

ASSISTANT: Ok, sure please wait for a while.

USER: Sure.

ASSISTANT: Sorry Lewis, no reservation found with your name in my system database.

USER: That is fine. Thank you for your time.

ASSISTANT: Thank you for reaching us.