You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I am looking to do some changes in my existing reservation. Can you help me for that?

ASSISTANT: Sure, I am here to help you with that changing reservation. May I know your name please?

USER: My name is Joseph Parker.

ASSISTANT: Please wait for a moment, let me check your previous reservation status.

USER: Sure, I will wait for your response.

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

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us. Have a great day.

USER: Welcome.