You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I am Brenda Thompson.

ASSISTANT: Ok.

USER: Owing to an emergency, I want to change an existing reservation. Could you help me in changing a reservation?

ASSISTANT: Please wait for sometime, I will check and revert to you.

USER: Sure.

ASSISTANT: We are sorry to notify, there is no reservation found on your given name.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for choosing us.