You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Karen Johnson.

ASSISTANT: How can I assist you?

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

ASSISTANT: Sure, I am happy to help you with that, give me a minute.

USER: Sure, take your time.

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

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: Thank you for contacting us, have a great journey.