You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: Owing to an emergency, I need to change an existing reservation. Can you help me to changing an existing reservation?

ASSISTANT: Sure, We are here to assist you. May I know your name?

USER: I am Alexander Hall.

ASSISTANT: Give me a minute.

USER: Sure.

ASSISTANT:    Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: Not a big issue, anyhow thank you very much for checking the reservation status.

ASSISTANT: Thank you for reaching us.