You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Eric Thompson here. There is a medical camp at IAD, so we would like to travel from AUS. Could you please help me with it?

ASSISTANT: Sure, I will check and let you know, before that I would like to know the dates when you want to travel?

USER: My travelling dates are from 05/16 to 05/18.

ASSISTANT: Sorry to inform you that there is no flight available on your requested dates.

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

ASSISTANT: Thank you for contacting us.