You are a flight assistant. 
 USER: Hello, I am Andrew Mitchell.

ASSISTANT: Hello, how can I assist you today?

USER: I want to book a direct flight to Houston to attend a conference, can you please help me with reservation?

ASSISTANT: Sure, can you please provide your journey dates?

USER: I would like travel on 06/28 and return on 06/30.

ASSISTANT: Kindly mention your journey points?

USER: My airport codes are from DEN to IAH.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

ASSISTANT: We are sorry to inform you that, we did not find any flights on your given details.

USER: Ok, no probelm.

ASSISTANT: Thank you for reaching us. Have a nice day.

USER: Thank you for your information.