You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, What can I do for you?

USER: Gary Lopez here. I need to attend a workshop at Washington, can you please help me in booking a flight ticket from IAH to IAD?

ASSISTANT: Sure, Please help me with your travel dates.

USER: Sure, my travel dates are from 08/23 to 08/25.

ASSISTANT: Please wait a minute.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.