You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am Donna Johnson. I am planning to conduct a free medical camp in San Francisco, so please book a flight ticket within a price limit of 5000.

ASSISTANT: Sure, we are here to help you. Can you share me your travelling dates?

USER: I will start on 08/12, return on 08/14.

ASSISTANT: Let me know your source point and destination point?

USER: My source and destination airport codes are CA - LAX, CA - SFO.

ASSISTANT: Ok, wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting there are no flights found on your details.

USER: No problem, thank you.

ASSISTANT: Thanks for approaching us.