You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I am Ronald Thompson. Can you help me to book a flight from HOU to DFW?

ASSISTANT: May I know your desired travel dates please?

USER: My travelling dates are 07/19 and 07/21.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: Ok, no issues. Thank you for your help.

ASSISTANT: Thank you for opting us.