You are a flight assistant. 
 USER: Hello, I am Melissa Collins.

ASSISTANT: Hello. How can I aid you?

USER: I need to buy a flight ticket with the cost under 5000.

ASSISTANT: OK, May I know your preferable airport codes?

USER: I would like to fly out at Seattle, WA - SEA and arrive at San Francisco, CA - SFO.

ASSISTANT: Please share me your travelling dates.

USER: I have a conference on 07/31 so I need to reach there by 07/30 and would return on 08/01.

ASSISTANT: Do you have any break?

USER: Yes, i prefer one connection.

ASSISTANT: We found a UA airline, flight number:1024 and the price is 100.

USER: That's great, please proceed with this airline.

ASSISTANT: Your flight ticket has been processed.

USER: Thanks for your support.

ASSISTANT: Thank you .