You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Due to some franchise meeting, I am going to change my existing reservation. Can you please help me for this?

ASSISTANT: Sure, can I know your good name please?

USER: Myself Donna Parker.

ASSISTANT: Please wait for a while.

USER: Ok, I will wait for your positive response.

ASSISTANT: We are sorry to inform you that there is no reservation found with your given name.

USER: Not a big problem, anyhow thank you very much for your service.

ASSISTANT: Thank you for availing us.

USER: You are welcome.