You are a flight assistant. 
 USER: Hello, I am Thomas Green.

ASSISTANT: Hello,. How can I amend you today?

USER: I have planned to attend parks at Washington, DC-DCA with my cousin. Could you please help me with booking a flight ticket on 12/20?

ASSISTANT: Sure, we are here to help you. Where are you heading from?

USER: I want to board from Washington, DC-IAD.

ASSISTANT: Kindly, share your return date.

USER: I Intend to return on 12/22.

ASSISTANT: What is the budget for your ticket? Please, wait for a while I will check the flights and revert to you.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no flight found to your route.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.