You are a flight assistant. 
 USER: Hello. I'm Gregory Evans.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Yes, please give me a moment, I will check your previous details.

USER: Ok.

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

USER: That's Ok.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your help.