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

ASSISTANT: Hello, how may I help you?

USER: I want to meet my friend on his birthday,can you help me in booking my flight ticket.

ASSISTANT: Sure, I am here to help you. To proceed for booking, Could you please provide me your schedule dates?

USER: My departure date is 09/17 and return date is 09/19.

ASSISTANT: OK, what are your travelling points?

USER: I want to travel from CO-DEN to TX-IAH.

ASSISTANT: Sure, please wait a moment.

USER: OK.

ASSISTANT: Thanks for waiting, sorry there are no flights found. Thanks for connecting us.

USER: OK, thanks for the information.