You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: As I am a scientist, I want to attend science festival with my students at Washington. Can you do the reservation?

ASSISTANT: Sure, please let me know your travel dates.

USER: Dates are 08/10 and 08/12.

ASSISTANT: Could you please provide me your airport codes?

USER: My airport codes are LAS-DCA.

ASSISTANT: May I know your name please?

USER: Angela Johnson here.

ASSISTANT: Sorry, there are no flights with your requirement.

USER: No problem, I will check with another airline.

ASSISTANT: Have a good day.