You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you today?

USER: I am Robert Evans here. I want to reserve my ticket from IAD to DEN, can you please help me?

ASSISTANT: Sure, please provide me your travelling dates.

USER: Sure, my planned dates of travel are from 11/12 to 11/14. I need a direct flight to travel.

ASSISTANT: Sorry, I could not find any flight with your travelling dates.

USER: Ok, no problem.

ASSISTANT: Thanks for choosing us.

USER: Anyways, thank you for your service.