You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Sharon Parker. I am here to request you to book a flight ticket from San Francisco to Houston under 1000 fare.

ASSISTANT: Sure, can I know your preferable dates?

USER: Ok, my preferable dates are 04/17 and 04/19.

ASSISTANT: Please, let me know your source and destination airport codes?

USER: CA - SFO is my source airport and TX - IAH is my destination airport.

ASSISTANT: Sorry, no flights available for given schedule.

USER: Ok, I will choose other way to reach my destination. Thanks for the information.

ASSISTANT: Thank you for reaching us.