You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: Dennis Anderson here. Can you please help me in booking my flight from DCA to visit places at OAK?

ASSISTANT: Sure, May I know your travelling dates?

USER: My planned travel dates are Aug 14th and 16th.

ASSISTANT: Do you have any connection limit?

USER: I need a single connecting flight.

ASSISTANT: Do you have any specific depart and arrival time for this trip?

USER: My depart time should be in the afternoon.

ASSISTANT: Is there any other preferences?

USER: No.

ASSISTANT: Thanks for your details. There are no flights found in the afternoon time.

USER: Ok, no problem. Anyways, thank you.

ASSISTANT: Thank you.