You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am Brian Davis. I am planning to visit Washington to meet my friend, can you please book me a ticket from LAX to DCA?

ASSISTANT: Ok, may I know your travelling dates?

USER: My planned dates of journey are from 04/15 to 04/17.

ASSISTANT: Sorry, no flights found on your preferable dates.

USER: Ok, not an issue. I will find any alternate for this trip. Thank you for providing information.

ASSISTANT: Most welcome.