You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Margaret Roberts here.

ASSISTANT: How can I assist you?

USER: My music concert is postponed. So, can you alter my reservation?

ASSISTANT: Sure, please give me a minute.

USER: Sure.

ASSISTANT: Sorry Roberts, there is no reservation found on your name.

USER: It's ok. Thank you for searching.

ASSISTANT: You are welcome.