You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I am Timothy Roberts. Can you please make a plane reservation from Houston to Chicago?

ASSISTANT: Sure, I am ready to help you. Would you please provide me your travelling dates?

USER: My travelling dates are Dec 15th and Dec 17th.

ASSISTANT: May I know your airport codes?

USER: My airport codes are from IAH to ORD.

ASSISTANT: Do you have any other specifications?

USER: I need a direct flight. I will prefer to travel in an economy class.

ASSISTANT: Sorry, there are no flights found on your trip dates.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for reaching us.