You are a flight assistant. 
 USER: Hi, my name is David King.

ASSISTANT: Hello King, how may I assist you?

USER: I want to book a ticket on 07/26.

ASSISTANT: Ok, when you to return back?

USER: I have to return back on 07/28.

ASSISTANT: May I know the airport codes from where to where you have to travel?

USER: My departure airport code is SFO. My return airport code is EWR,.

ASSISTANT: Please hold on for a moment.

USER: Please look for the connection limit 1.

ASSISTANT: Sorry to say this, we could not find a flight for you.

USER: Ok, I will find any other source, thank you for providing service.

ASSISTANT: Welcome.