You are a flight assistant. 
 USER: Hello. I am Helen Lee.

ASSISTANT: Hello, how may I help you today?

USER: I have a plan to visit Franklin Institute in Philadelphia to exhibit my painting. Can you please make a plane reservation with halt?

ASSISTANT: Sure, may I know your source and destination airport codes?

USER: My origin code is San Francisco CA-SFO and destination code is Philadelphia PA-PHL.

ASSISTANT: Could you please provide me your journey dates?

USER: My departure date is 01/13. I intend to return on 01/15.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, no flights found with your given details.

USER: Ok, no worries at all. Thank you for your kind service.

ASSISTANT: Thank you for opting us.