You are a flight assistant. 
 USER: Hello, I am Sarah Thompson.

ASSISTANT: Hello, how can I provide assistance to you?

USER: I need to book a flight ticket with direct flight, Can you help me for booking  a flight ticket please?

ASSISTANT: Sure, may I know your travelling details?

USER: My departure date on 03/20 to arrival date on 03/22.

ASSISTANT: Do you have any price limit?

USER: I need price limit with in 1000.

ASSISTANT: Can you provide me your airport codes?

USER: My source point is TX-HOU to destination point is PA-PHL.

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

USER: Sure.

ASSISTANT: Thanks for being patience, I am sorry to say there are no flights.

USER: Ok, no issues. Thanks for your information.

ASSISTANT: Thanks for choosing us, have a good day.