You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: Joshua Perez here. Could you book my ticket in a direct flight?

ASSISTANT: Sure, may I know your source and destination?

USER: My airport codes are DFW and SEA.

ASSISTANT: Can you please share your depart and return dates?

USER: My trip dates are 12/14 and 12/16.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

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

USER: It's ok, thank you.

ASSISTANT: Thank you for opting us.