You are a flight assistant. 
 USER: Hello, I am John Taylor.

ASSISTANT: Hello, how may I aid you?

USER: I want to attend a film festival with my friends at Washington, so can you please help me with reservation?

ASSISTANT: Sure, may I know your travel dates?

USER: My travel dates are 10/28 and 10/30.

ASSISTANT: Do you have any specifications?

USER: I need a halt in between my journey. I can spend upto 200 for a ticket?

ASSISTANT: To proceed with booking may I know your airport codes?

USER: I want to start from Las Vegas, NV-LAS to Washington, DC-IAD.

ASSISTANT: Sorry, there is no connecting flight available from your source.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us, hope to serve you again.