You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how shall I help you?

USER: I am Nancy Perez, I plan to visit my friends house but we postponed our plan. I want to change my reservation with new dates.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: No reservation found by name Nancy Perez.

USER: Ok, thanks for the information.

ASSISTANT: Thanks.