You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: My name is Nicole Lopez. I want to book a flight to Houston to meet my mother, can you please help me to book  a flight from Washington DC?

ASSISTANT: Sure, can I know your preferable dates?

USER: I will depart on July 25th and return back on July 27th.

ASSISTANT: Ok, let me know the airport code of Houston and Washington?

USER: The airport code for Houston is IAH and Washington DC is IAD.

ASSISTANT: Sorry, there are no flight found on given schedule.

USER: Never mind, thank you for checking it.

ASSISTANT: Thank you for reaching us.