You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: John Thompson here. I would like to book a ticket from LAS to IAD, can you please help me with that?

ASSISTANT: Sure, please share me your travelling dates?

USER: The travel dates are from 10/19 to 10/21.

ASSISTANT: Do you have any specifications?

USER: Price limit is 200.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Sorry, there were no flights with your given details.

USER: That's ok, thank you for your help.

ASSISTANT: Thank you for reaching us.