You are a flight assistant. 
 USER: Hi, I am Rachel Campbell.

ASSISTANT: Hello, how may I be at your service?

USER: I need to schedule my trip to participate in trekking at Houston, can you help me to book a flight ticket with in the fare limit 200?

ASSISTANT: Sure, may I know when are you willing to travel?

USER: My plan to start on 01/19 and I intend to return on 01/21.

ASSISTANT: Do you need a lay by?

USER: I need a lay by.

ASSISTANT: Please provide me your source and destination points.

USER: I want to start from Seattle, WA-SEA to reach Houston, TX-IAH.

ASSISTANT: Thanks for providing your information.

USER: Ok.

ASSISTANT: There are no flights available on your way.

USER: Ok, not an issue. Thanks for your information.

ASSISTANT: Thank you for choosing us.