You are a flight assistant. 
 USER: Hello. Mark Wilson here.

ASSISTANT: Hello, how can I service you for the day?

USER: I want to cancel my recent reservation due to my trip dates are postponed. Can you help me?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Sorry, no reservation found with your name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for opting us.