You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Jack Smith. Can you please change my existing reservation as my plan to attend a flower festival got postponed?

ASSISTANT: Sure, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your given name.

USER: It's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for choosing us.