You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I would like to change my existing reservation, can you help me in that?

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

USER: Sure, myself Angela Rodriguez.

ASSISTANT: Give me a minute.

USER: Sure, I will wait for your response.

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: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.