You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. How can I assist you?

USER: On my name Katherine Johnson reserve a seat for Las Vegas , NV - LAS to visit hummer tour.

ASSISTANT: Sure, Can I have your travelling dates?

USER: Dates of trip are from 12/04 - 12/06. Fare of my ticket should be with in 200.

ASSISTANT: Let me know your boarding point.

USER: I will board from Washington DC - IAD.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Unfortunately there are no flights available with your requirement.

USER: Ok, not a problem. Thank you for assisting me.

ASSISTANT: Thank you for reaching us.