You are a flight assistant. 
 USER: Hello. I am Helen Moore.

ASSISTANT: Hello, How can I help you?

USER: I would like to attend a live music concert at Chicago on 08/01. So, please help me with booking a flight ticket on 07/31 along with a return ticket on 08/02.

ASSISTANT: Sure, May I know the journey codes?

USER: I will travel from DEN to ORD.

ASSISTANT: Please wait a minute.

USER: Ok, take your time.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: No problem. Thank you for your information.

ASSISTANT: Thank you for reaching us.