You are a flight assistant. 
 USER: Hello, Barbara Carter here.

ASSISTANT: Hello, how can I provide assistance to you?

USER: I need to book a ticket from Charlotte, NC-CLT to Houston, TX-HOU on 04/21 as I need to attend a house warming ceremony.Could you please help me with booking?

ASSISTANT: Sure, we are here to help you. Can you please provide me your date of return?

USER: Yes, my return date is 04/23.

ASSISTANT: OK, please wait a moment.

USER: OK.

ASSISTANT: Thanks for you time. sorry to inform no flight found with your requirement.

USER: Thank you for your response.

ASSISTANT: Have a good day.