You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Daniel Thomas.

ASSISTANT: How may I aid you?

USER: May I know if you can change the reservation which I had done last week?

ASSISTANT: Sure, I am here to help you. Sorry, there are no reservation found on your name.

USER: That is ok, thank you for assisting me.

ASSISTANT: Thank you for choosing us.