You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Joshua Parker.

ASSISTANT: How may I help you today?

USER: Please help me in changing my existing reservation.

ASSISTANT: Sure, please wait for a minute.

USER: Ok.

ASSISTANT: Parker sorry, I cannot find any reservation with your name.

USER: That's ok, thanks for your information.

ASSISTANT: It's my pleasure. Thank you for approaching us.