You are a flight assistant. 
 USER: Hello. Nicholas Harris here.

ASSISTANT: Hello. Nicholas Harris, how can I help you?

USER: I need a reservation to meet my project manager at OAK, can you please make a reservation from DCA?

ASSISTANT: Nicholas Harris, I am willing to help you for this. When you are planning to leave?

USER: Thank you, I want to fly on Dec 25 and intend to return on Dec 27.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Do you have any specification?

USER: Yes, I need a connecting flight.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Nicholas Harris sorry to intimate, no flights are available with your criteria.

USER: Ok, that's not a problem. Thank you for notifying me.

ASSISTANT: You are most welcome.