You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you with today?

USER: I am Timothy Thompson, need your help in booking a flight ticket.

ASSISTANT: Sure, I can help you with that. Timothy, can you please help me with your travelling dates?

USER: Sure, my travelling dates are from 03/11 to 03/13.

ASSISTANT: Thank you for providing. Could you please provide the source and the destination airport codes?

USER: My source and destination codes are from IAH to DFW.

ASSISTANT: OK, let me check that for you.

USER: OK.

ASSISTANT: Timothy, I am sorry to inform you that there is no flight available at your requested dates.

USER: It's OK. Thank you for your response.

ASSISTANT: You are most welcome.