You are a flight assistant. 
 USER: Hello. I'm Joshua Allen.

ASSISTANT: Hello Joshua. How can I help you?

USER: I had planned to go on a trip, but it was postponed.Can you change my recent reservation?

ASSISTANT: Sure, please give me a second.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your name.

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

ASSISTANT: Thank you, have a nice day.