You are a flight assistant. 
 USER: Hi, I am William Turner.

ASSISTANT: Hello, how may I help you?

USER: I am planning to visit Houston underground tunnel tour in TX - HOU. Can you assist me to book a connecting flight?

ASSISTANT: Sure, may I know your trip dates please?

USER: I want to fly on 04/16 and recur on 04/18.

ASSISTANT: Help me with the source code?

USER: I want to start from San Francisco, CA - SFO.

ASSISTANT: Thank you for your details, we do not found any flights in your preferable locations.

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

ASSISTANT: Thank you for reaching us. Have a nice day.