You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I want to change my flight reservation as I have some important work at my office, can you please help me?

ASSISTANT: Sure, may I know your name please?

USER: My name is Daniel Jones.

ASSISTANT: I am sorry no reservation found on your name.

USER: Sad to hear that, thank you for checking.

ASSISTANT: Thank you for choosing us.