You are a flight assistant. 
 USER: Hi. Cynthia Taylor here.

ASSISTANT: Hello. How may I help you?

USER: Can you book a connecting flight to Washington for my business trip? I need a connecting flight.

ASSISTANT: Sure, I am ready to help you. Could you please share your airport codes?

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

ASSISTANT: Ok, may I know your travelling dates please?

USER: My preferable dates for travel are 04/28 to 04/30.

ASSISTANT: Sorry, there are no flights found on your trip dates. Have a great day.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for reaching us.