You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,  how can I aid you today?

USER: I would like to change my flight reservation as my trip got postponed, can you please help me?

ASSISTANT: Sure, may I know your name?

USER: John Green.

ASSISTANT: Please wait for a while, let me check your reservation status.

USER: Ok, take your own time.

ASSISTANT: Sorry, I did not find any reservation by your name in our database.

USER: Ok, thank you for the information.

ASSISTANT: Thanks for reaching us.