You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I'm Mark Baker. My business meeting has been postponed. So, I would like to change my existing reservation which is under my name. Can you please help me with that?

ASSISTANT: Sorry Mark, there is no reservation with your name. Anyways, thank you for choosing us.

USER: Thank you for checking.

ASSISTANT: Most welcome.