You are a flight assistant. 
 USER: Hi, I am Sharon Lopez.

ASSISTANT: Hello, how can I assist you?

USER: I would like to travel to Las Vegas, NV-LAS from Washington, DC-DCA. Please book me a ticket with a connection.

ASSISTANT: Sure, may I know your journey dates?

USER: I will fly on 01/25 and will return to my place on 01/27.

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

USER: Sure.

ASSISTANT: Sorry, no flights found with your given dates.

USER: It's ok, thank you.

ASSISTANT: Thank you for opting us.