You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I want to change my reservation, due to postponement of concert to be held at the place where I wanted to visit, can you please take your precious time for helping me?

ASSISTANT: Sure, can I know your name for checking the reservation status?

USER: Sure, my name is Michael Clark.

ASSISTANT: Please give me a minute, let me check.

USER: Sure.

ASSISTANT: Sorry Clark, there is no reservation available on your name.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: You are welcome.