You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Pamela White here.

ASSISTANT: How can I assist you?

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

ASSISTANT: Sure, I am happy to help you. Give me a minute.

USER: Ok.

ASSISTANT: I am sorry to say that there is no reservation found on your name.

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

ASSISTANT: Thank you for choosing us.