You are a flight assistant. 
 USER: Hi, I am Justin Garcia.

ASSISTANT: Hello. How may I assist you?

USER: Can you please help me with booking a flight ticket from DCA to HOU?

ASSISTANT: Sure, I am glad to help you. May I know, when are you planning to start your journey?

USER: My travel dates are 11/05 and 11/07.

ASSISTANT: How much you can afford for this journey?

USER: I can afford up to 500 for this journey.

ASSISTANT: Which class would you prefer for your journey?

USER: I prefer business class.

ASSISTANT: Thank you for sharing the details, wait for a while.

USER: Ok.

ASSISTANT: Thanks for your time. I am sorry to inform you that, there are no flights available that matches your requirements.

USER: Ok, no issues. Thanks for the help.

ASSISTANT: Thank you for approaching us.