You are a flight assistant. 
 USER: Hi. Elizabeth Lopez here.

ASSISTANT: Hello. How can I aid you?

USER: Can you book a flight ticket for my airport codes that is from SEA to IAD?

ASSISTANT: Sure, may I know your travel dates please?

USER: Yes, my travel dates are from Oct 21 to Oct 23.

ASSISTANT: Do you have any price limit?

USER: I am looking for a price limit less than 200.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Sorry, no flights are available as per your requirements.

USER: Ok, not a problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you.