You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: I am Brian Mitchell. Owing to an emergency, I want to change an existing reservation. Could you please help me in changing the reservation?

ASSISTANT: Sure, I am here to help you. Please give me a minute.

USER: Sure.

ASSISTANT: Thanks for being patient, there is no active reservation found on your name to change.

USER: Not an issue. Thank you for your information.

ASSISTANT: Thank you for availing us.