You are a flight assistant. 
 USER: Hello. I'm Michael Brown.

ASSISTANT: Hello, how may I help you?

USER: I had planned to visit my friend, but it was postponed.Can you change my recent reservation?

ASSISTANT: Ok Brown, just wait for a while.

USER: Sure.

ASSISTANT: Sorry Brown, there is no reservation found with your name to change in our database.

USER: That's Ok. Thank you for your help.

ASSISTANT: You are welcome.