You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you now?

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

ASSISTANT: Sure, I am gleeful to help you with that.

USER: Thank you.

ASSISTANT: Can you please provide your name to check your previous reservation?

USER: My name is Carol Thompson.

ASSISTANT: Please wait a moment.

USER: Sure, I will wait for your response.

ASSISTANT: We regret to inform you that, there is no reservation on your name in our records.

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

ASSISTANT: Thank you for contacting us, have a great day.

USER: Welcome.