You are a flight assistant. 
 USER: Hello. I am Brandon Martinez.

ASSISTANT: Hello, how can I assist you today?

USER: I need to book a ticket to meet my friend on his birthday from DFW to DEN. Could you please help me in booking a ticket with fare of 500?

ASSISTANT: Sure, may I know your planned journey dates?

USER: My travelling dates are 01/23 and return on 01/25.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there are no flights found with your given details.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for choosing us.