You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your name please?

USER: Sure, my name is Susan Brown.

ASSISTANT: How can I assist you?

USER: I would like to visit Desert Botanical Gardens in Phoenix, AZ - PHX. Will you help me to book a flight ticket on 10/27?

ASSISTANT: Sure, do you have any price limit?

USER: Yes, I should be under 5000.

ASSISTANT: Please provide your source code?

USER: Sure, my source is Houston, TX - HOU.

ASSISTANT: When you are willing to return?

USER: I would like to return on 10/29.

ASSISTANT: Sorry for the inconvenience, there were no flights found with your given preferences.

USER: No problem, thanks for your service.

ASSISTANT: Thank you for availing us.