You are a flight assistant. 
 USER: Hi. Sandra Phillips here.

ASSISTANT: Hello Sandra, how may I help you?

USER: Yes, find a flight for me from OAK to SFO. As I am planning a business meeting on stock markets in San Francisco.

ASSISTANT: Sure, please provide your itinerary dates.

USER: My preferable dates for travel are 04/05 to 04/07.

ASSISTANT: Please hold on for a while.

USER: Ok.

ASSISTANT: Sorry, no flight is available on your planned dates.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you.