You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I need to change my reservation due to my planned event got postponed so please help me with that.

ASSISTANT: Sure, I am blissful to help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Sure, myself Sarah Smith.

ASSISTANT: Please wait for a moment.

USER: Sure, take your time.

ASSISTANT: Thanks for waiting. I regret that there is no reservation found on your name.

USER: Oh! May be booking is not done properly. Anyway, thank you for your time.

ASSISTANT: Thank you for choosing us.

USER: Welcome.