You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I am Anna Robinson here, I want to reserve my ticket from IAD to MSP, can you please help me?

ASSISTANT: Ok, please provide your journey dates too.

USER: Sure, my preferable dates of travel are from 08/20 to 08/22.

ASSISTANT: Sorry, there is no flight available on your route.

USER: Ok, that's fine.

ASSISTANT: Thanks for choosing us.

USER: Anyways, thank you for your service.