Hi, I am Sarah Roberts.
user
Hello, how can I assist you?
assistant
 I need to book a ticket for attending my friends grand event which is held at Washington DC-DCA on 04/18.
user
Ok, I can help you with that. Can you please provide your origin and return date?
assistant
Sure, I will return to Chicago ORD on 04/20.
user
Please wait a moment. I will check the availability.
assistant
Sure.
user
Thanks for your patience. Unfortunately there are no flights available with your requirements.
assistant
No problem, Thank you for searching.
user
Thanks for connecting with us. Have a good day.
assistant