You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I render you today?

USER: I want to book a flight ticket from DCA to SFO, can you please help me?

ASSISTANT: Sure, could you please share your journey dates?

USER: I planned my trip on the dates Feb 9 and Feb 11.

ASSISTANT: May I know your good name?

USER: Myself Gregory Walker.

ASSISTANT: Do you have any preferences?

USER: I am looking for a connecting flight and make sure to check with the evening flight at the time of depart.

ASSISTANT: Sorry, there are no flights available as per your requirements.

USER:  No issue, anyway thank you for checking.

ASSISTANT: Thank you for opting us.