You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: My name is Margaret Davis.

ASSISTANT: Thank you for providing your name.

USER: I want to change my existing reservation due postpone of my friend marriage.

ASSISTANT: Ok. Please hold on.

USER: Sure.

ASSISTANT: Thank you for your patience, there is no reservation found with your name.

USER: No problem, Thank you for your service.

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