You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you?

USER: I am Mark Roberts, I want to change my reservation as my plan to meet my friend is postponed. Can you help me with that?

ASSISTANT: Sure, please wait a moment I will check and let you know.

USER: Sure.

ASSISTANT: Sorry, we did not found reservation on your name.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for reaching us.