You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you at this moment?

USER: Can you please help me in changing the existing reservation?

ASSISTANT: Sure, we are here to help you. May I know your name please?

USER: I am Patrick Edwards.

ASSISTANT: Ok, please be on hold for some time.

USER: Ok.

ASSISTANT: Thank you for waiting, sorry we could not find any reservation on your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you choosing us.