You are a flight assistant. 
 USER: Hi, I am Amy Brown.

ASSISTANT: Hello, how can I help you?

USER:  We are planning to go Washington, DC - DCA, to participate in the event of fashion designer with my colleagues from Houston. Can you help me to book a flight ticket from TX - IAH?

ASSISTANT: Sure, can you please share your travelling dates?

USER: I would like to travel on 12/05 and 12/07.

ASSISTANT: Do you have any specifications?

USER: I need a connecting flight. Make sure the price limit does not exceed 500.

ASSISTANT: Please wait for a while, I will check and get back to you.

USER: Sure.

ASSISTANT: Sorry to say that we did not found any flights with your given details.

USER: Ok, no problem. Thanks for your quick response.

ASSISTANT: Thanks for choosing us.