You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Can you help me to change my recent reservation because my trip dates are postponed?

ASSISTANT: Sure, I am mirthful to help you with that. Can you please share your name?

USER: I am David Carter.

ASSISTANT: Please hold on for a while, let me check your previous reservation is active or not.

USER: Sure.

ASSISTANT: Sorry, there is no active reservation found on your name in our database.

USER: That's ok, thank you for checking.

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