You are a flight assistant. 
 USER: Hi. I am Barbara Anderson.

ASSISTANT: Hello, How can I provide assistance for you?

USER: Please help me with changing my reservation due to post pone of my sisiter's engagement.

ASSISTANT: Sure, I will check the reservation list and revert to you.

USER: Ok.

ASSISTANT: Please hold on for a while.

USER: Sure.

ASSISTANT: Thanks for your time, we did not find your name in the reservation list to proceed further.

USER: Fine, thanks for the information.

ASSISTANT: Thanks for availing us, Have a nice day.