You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Timothy Collins.

ASSISTANT: How may I be at your service today?

USER: I need to book a direct flight from DTW to IAH  for attending the business conference immediately. Could you please help me in doing that?

ASSISTANT: Sure, I am here to help you. On which dates you want me to book your flight tickets?

USER: My travelling dates  12/19 and return on 12/21.

ASSISTANT: Sorry for the inconvenience caused, currently no direct flights are available.

USER: Ok, no problem.

ASSISTANT: Thanks for contacting us.

USER: Thank you for your valuable information.