You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Joshua Collins.

ASSISTANT: How may I guide you today?

USER: Can you help me in changing my recent reservation, as my exam is postponed?

ASSISTANT: Sure, I will help you with that.

USER: Ok.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: I am sorry to say that there is no reservation found under your name.

USER: That's ok, thank you.

ASSISTANT: Thank you for reaching us.