You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I address you?

USER: Would you please help me to book a flight from OAK to reach San Francisco?

ASSISTANT: Sure, when are you planning to make your trip?

USER: My planned dates are on Apr 13th to 15th.

ASSISTANT: How many lay by's do you need in between your journey?

USER: No, I need a direct flight.

ASSISTANT: May I know your name?

USER: Sure, Patricia Nelson is my name.

ASSISTANT: Do you have any specifications?

USER: No.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thank you for waiting, I regret to inform you that there are no flights obtained on your journey dates to book a flight ticket.

USER: No issues, thank you.

ASSISTANT: Thank you for approaching us.