You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you for the day?

USER: Can you help me to change my existing reservation?

ASSISTANT: Sure, may I know your name please?

USER: I am Joshua Baker.

ASSISTANT: Ok, please be on hold.

USER: Ok.

ASSISTANT: Sorry  we could not find any reservation on your name.

USER: It's ok, thank you.

ASSISTANT: Thank you for choosing us.