You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I serve you?

USER: I am Dennis Hernandez. I want to book a flight ticket to celebrate my birthday in Phoenix AZ - PHX, so please help me in booking a flight ticket from Oakland CA - OAK.

ASSISTANT: Sure, May I know the travel dates?

USER: I want to fly on 09/14 and return on 09/16.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for reaching us.