You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Myself Rebecca Perez. I would like to meet my friend at Oakland, will you help me in booking the flight ticket from IAD to OAK?

ASSISTANT: Sure, I am here to help you with that. Could you please share your travel dates?

USER: My travelling dates are 12/20 and 12/22.

ASSISTANT: Ok, I will search the flight for you. Please be on hold for a minute.

USER: Ok, I will wait for your response.

ASSISTANT: I regret to inform you that, I have not found any flight which is available in this route on the dates you have provided to me.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: You are welcome. Thank you for reaching us. Have a nice day.