You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you now?

USER: I am Mark Scott. I am planning to travel from DTW to IAD.

ASSISTANT: Sure, can you please mention the travelling dates of your journey?

USER: My date of travelling is on 08/18 to 08/20.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry Mark, there are no flights found on your requested dates.

USER: That's ok. Than you for your help.

ASSISTANT: Thank you for approaching us, have a nice day.