You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you for today?

USER: I want to change my reservation, can you help me?

ASSISTANT: Sure, I will help you about that. Can you please provide your name for checking the reservation status?

USER: I am Mark White.

ASSISTANT: Give me a moment.

USER: Sure.

ASSISTANT: Sorry for the trouble which is caused to you, I have not found any reservation on your name in our database.

USER: No problem, thanks for checking.

ASSISTANT: You are welcome, thank you for reaching us.