You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: I am Ronald Collins. I am planning to travel from DCA to IAH.

ASSISTANT: Sure, can I know the travel dates please?

USER: My travelling dates are 07/20 to 07/22.

ASSISTANT: Sorry, there are no flights available on your dates.

USER: That's ok.

ASSISTANT: Thank you for approaching us.

USER: Thank you.