You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, may I know your name?

USER: Michael White here.

ASSISTANT: Ok, please wait for sometime.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found on your name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for reaching us.