You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: My name is Gregory Thompson. I would like to travel from DCA to IAH, could you help me out?

ASSISTANT: Sure, can I know your travel dates?

USER: My preferable dates are from 03/04 to 03/06.

ASSISTANT: Ok, please wait. I will check for the available flights and let you know.

USER: Sure.

ASSISTANT: Gregory, there is no flight available on your preferred dates.

USER: That's ok. Thank you, have a good day.

ASSISTANT: You are welcome and thank you for choosing us.