You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I am Mary Campbell. I want to change my reservation, can you help in changing?

ASSISTANT: Sure, please wait a moment I will check your reservation details and proceed further.

USER: Sure.

ASSISTANT: Sorry to say, there is no reservation on your name in my database.

USER: That's ok.

ASSISTANT: Thank you for choosing us, have a nice day.

USER: Thank you for your help.