You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am Rachel Allen.

ASSISTANT: Yes, Allen.

USER: I am planning to change an existing reservation, due to exams. Can you please change my reservation?

ASSISTANT: Sure, please be online. I will check your reservation status.

USER: Sure, take your own time.

ASSISTANT: There is no reservation found under your name in our database, Allen.

USER: That's fine. Thank you for your help.

ASSISTANT: Thank you for choosing us.