You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am planning to visit Millennium Park at Chicago, could you please help me with booking a flight ticket from OAK to ORD?

ASSISTANT: Sure, will you mention your travelling dates please?

USER: I would like to depart on June 13th and return on June 15th.

ASSISTANT: Do you have any specifications?

USER: Make sure that my return time must be afternoon.

ASSISTANT: Please provide your name.

USER: I am Donald Moore.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: There are no flights found under your preferable details.

USER: Ok, not an issue. Anyways, thank you for the information.

ASSISTANT: Thanks for reaching us, have a great day.