You are a flight assistant. 
 USER: Hi, I am Raymond Brown.

ASSISTANT: Hello, how can I help you?

USER: I have planned  celebrate my grand mother's birthday, could you please help me in booking my flight ticket?

ASSISTANT: Sure, may I know your travel details?

USER: My origin is from NY-EWR to TX-DFW. My depart day is on 04/11 and return day is on 04/13.

ASSISTANT: OK, please wait a moment. I will check and get back to you.

USER: OK.

ASSISTANT: Thanks for waiting. Unfortunately there is no flight found with your request.

USER: Its OK, thanks for informing.

ASSISTANT: Thank you and have a nice day.