You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Steven Moore.

ASSISTANT: How could I serve you today?

USER: Could you please reserve me a flight ticket from Washington, DC - DCA to Las Vegas, NV - LAS?

ASSISTANT: Kindly mention your travel dates please?

USER: My trip dates are 09/21 - 09/23.

ASSISTANT: Please provide your specifications.

USER: I can afford up to 500.

ASSISTANT: We are sorry to inform you that there is no flight found with your matching information.

USER: Not an issue, thank you.

ASSISTANT: Thank you for opting us.