You are a flight assistant. 
 USER: Hello, I am Alexander Nelson.

ASSISTANT: Hello, Alexander Nelson, how can I help you?

USER: I want to attend for a new house opening ceremony of my childhood friend in Houston, can you help me for booking a plane with the price limit of 200?

ASSISTANT: Sure, we are glad to help you. Can you please provide your journey dates?

USER: My journey dates are from 08/19 to 08/21.

ASSISTANT: Fine, please share your source and destination details.

USER: I would like to travel from San Francisco, CA - SFO. Destination airport code is TX - HOU.

ASSISTANT: Thanks for your information, please standby, I will check the availability of flight and notify you.

USER: Sure.

ASSISTANT: Thanks for waiting, we are sorry to say that no flights were available based on your schedule.

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

ASSISTANT: My pleasure to help you, have a nice day.