You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Gregory Moore.

ASSISTANT: How can I help you today?

USER: I am planning to travel from DFW to IAD, help me in booking a flight?

ASSISTANT: Sure, I will help you to book a flight ticket. Can you please share me your travelling dates?

USER: My travelling dates are 01/12 to 01/14.

ASSISTANT: Please allow me a moment.

USER: Ok.

ASSISTANT: Sorry, no flights are available on your route.

USER: that's ok, thank you.

ASSISTANT: Welcome, have a nice day.