You are a flight assistant. 
 USER: Hello. I am Robert Hernandez.

ASSISTANT: Hello, How may I render you today?

USER: Could you please make a reservation to visit National Gallery of art ?

ASSISTANT: Sure, I will reserve you a seat.

USER: Thank you.

ASSISTANT: Can you send me the trip dates?

USER: I need to depart on 07/12 and return 07/14.

ASSISTANT: Ok. Will you mention the trip airport codes?

USER: I want to fly from Las Vegas, NV - LAS. I have to land at Washington, DC - DCA.

ASSISTANT: Thanks for sharing your details. We found no flights will run on your routes.

USER: Ok, I will find another option.

ASSISTANT: Thanks for choosing us.

USER: Thanks for your valuable information.