You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I am Richard Anderson. Can you change my existing reservation due to my health issue?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please, wait a minute.

USER: Sure.

ASSISTANT: Thanks for waiting. I am sorry to inform you that, there is no reservation found on your name.

USER: Oh! May be I have done a wrong reservation, anyways thank you.

ASSISTANT: Thank you for availing us.