You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you?

USER:  I am Joshua Brown, please change my reservation as I postponed my plan to visit my friend.

ASSISTANT: Sure, I will check your recent reservation and get back to you.

USER: Ok.

ASSISTANT: Unfortunately, no reservation found on your name.

USER: Thank you for the information.

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