You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I am Larry Lewis. I would like to change my existing reservation. Could you help me out?

ASSISTANT: Ok Larry, Please be on hold let me check your details in our database.

USER: Sure.

ASSISTANT: Thank you for your patience, there is no reservation found in our database.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: You are welcome, thank you for reaching us.