You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: As I am a scientist, I want to attend science festival with my students at Washington. Can you do the reservation?

ASSISTANT: Great! I will help you.

USER: Thank you.

ASSISTANT: Please let me know with your planned travel dates.

USER: My journey dates are 08/25 and 08/27.

ASSISTANT: May I know with your source and destination airport codes please?

USER: My airport codes are MSP-DCA.

ASSISTANT: May I know with your name please?

USER: Rebecca Phillips here.

ASSISTANT: Rebecca Phillips, do you need a connecting flight?

USER: I need break in my journey.

ASSISTANT: Please help me with your depart and return time.

USER: My departure time is afternoon.

ASSISTANT: Thank you. Do you have any other preferences?

USER: No.

ASSISTANT: Rebecca Phillips, I am sorry to inform you that there are no active flights available.

USER: No problem, Thanks for the information.

ASSISTANT: Thank you for reaching us. Have a great time.