You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello. How may I aid you today?

USER: I want to change my existing reservation due to my exams got postponed. Can you aid me with this?

ASSISTANT: Sure, for that I need to know your name please provide it.

USER: Myself Nancy Collins.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Thanks for your time, we did not found any reservation by this name.

USER: Ok, thanks for your kind response.

ASSISTANT: Thanks for opting us.