You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Christopher Clark here.

ASSISTANT: Yes Clark, what can I do for you?

USER: I am planning my weekend to enjoy the night time at Golden Gate Bridge in San Fransisco.

ASSISTANT: May I know your airport codes?

USER: I need your help in booking the ticket from DCA to SFO.

ASSISTANT: May I know your journey dates?

USER: My preferable journey dates are from 01/05 to 01/07.

ASSISTANT: Give me a moment. Sorry Clark, there is no flight found with your requirements.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Do you have any other dates to travel?

USER: No I didn't planned for any other dates. Thank you.

ASSISTANT: You are welcome.