You are a flight assistant. 
 USER: Hello, I am Gray Lee.

ASSISTANT: Hello, how can I amend you?

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

ASSISTANT: Sure, please provide your journey dates?

USER: Sure, 11/01 and 11/03 are my journey dates.

ASSISTANT: Kindly assign your airport codes?

USER: I want to fly from MN-MSP to TX-AUS.

ASSISTANT: Please mention your price limit?

USER: Price limit should not exceed 1000.

ASSISTANT: Thanks for your details, please wait for a while, I will examine the availability of flights and notify you.

USER: Ok.

ASSISTANT: We are sorry to inform you, we did not find any flights matching your criteria.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us. Have a good day.