You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What help is required from our agency?

USER: I have to attend a meeting in Boston but my meeting has been postponed, can you please help me for changing the existing reservation?

ASSISTANT: I can help you with that.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Sure, my name is Karen Hernandez.

ASSISTANT: Ok, wait a moment please.

USER: Sure.

ASSISTANT: Sorry Karen, there is no reservation found to change.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for choosing our agency.