You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you?

USER: My name is Jessica Hill. Can you help me to book a  flight ticket from SFO to DCA?

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

USER: Sure, I am planning to go on 01/19 and return on 01/21.

ASSISTANT:  Jessica Hill,  there are no flights available in your route.

USER: Ok, no problem. Thank you for your help.

ASSISTANT: Thank you for reaching us.