You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Benjamin Smith.

ASSISTANT: how can I help you Mr.Smith?

USER: As my business meeting is postponed, I want to change my existing reservation. Can you help me?

ASSISTANT: Sure, I will help you.

USER: Ok.

ASSISTANT: Sorry, no reservation found on your name.

USER: No issue, thank you for checking.

ASSISTANT: Thank you for contacting us.