You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: Rebecca Moore here. I am looking for a connecting flight to Washington. Can you book a flight ticket?

ASSISTANT: Sure, may I know your journey dates?

USER: My preferable dates for travel are 07/02 to 07/04.

ASSISTANT: Can you provide your airport codes for booking?

USER: My airport codes for boarding the flight are SFO to IAD.

ASSISTANT: Give me a minute.

USER: Ok.

ASSISTANT: Sorry, there is no flight on your given dates.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for reaching us.