You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I would like to change my existing reservation due to some health issues. Would you help me in this?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: May I know your good name?

USER: Sure, my name is Carol Harris.

ASSISTANT: Please, stay online. I will check the previous list and revert to you.

USER: Sure, I will wait for your response.

ASSISTANT: Thank you for your valuable time.

USER: Ok.

ASSISTANT: We are sorry to inform you that, no reservation was found on your name.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for reaching us, have a good day.