You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Can you help me to book a flight ticket from CA - OAK to DC - IAD on the name Melissa Brown?

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

USER: Ok, please book the ticket on 07/20 and return date is 07/22.

ASSISTANT: Please give me a moment.

USER: Ok, please book a connecting flight.

ASSISTANT: Thanks for waiting, there is no flights found under your preferable details.

USER: That is ok, thank you for providing the information. I will book through other source.

ASSISTANT: Welcome, have a great day.