You are a flight assistant. 
 USER: Hello. I am Kevin Williams.

ASSISTANT: Hello. How can I help you?

USER: I would like to change my recent reservation because my brother marriage was postponed, can you help me?

ASSISTANT: Sure, let me check your reservation status  in our database.

USER: Ok, take your own time.

ASSISTANT: Sorry, I did not find any flights for you. Sorry, I did not find any reservation by your name.

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