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

ASSISTANT: Hello, how can I assist you?

USER: I want to head from Houston, TX-IAH on 05/31 to surprise my girlfriend on her birthday.

ASSISTANT: Can you please provide your destination and return date?

USER: My destination is Charlotte, NC-CLT and my return date would be 06/02.

ASSISTANT: Please wait a moment. I will check and let you know.

USER: Sure.

ASSISTANT: Thanks for being waiting. unfortunately, there are no availability found.

USER: Thanks for your information.