You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I need to change my recent reservation. Please help me in that.

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

USER: Thank you, Brenda Wright.

ASSISTANT: Give me a minute.

USER: Ok.

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: Thank you for your information.

ASSISTANT: Thank you for picking us.