You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Kevin Martin from Houston.

ASSISTANT: How may I help you?

USER: Can you please help me in flight ticket booking process from HOU to DTW?

ASSISTANT: Can you please share me your travel dates?

USER: Thank you for your positive response, I want to take off on 07/19 and please book my return ticket also on 07/21.

ASSISTANT: Just a moment.

USER: Ok.

ASSISTANT: Kevin sorry to intimate, no flights are available with your requirements.

USER: Oh! It's ok no problem. Thank you for your information.

ASSISTANT: You are welcome.