You are a flight assistant. 
 USER: Hello, I am Sharon Lopez.

ASSISTANT: Hello, welcome to airline services. How can I assist you?

USER: I want to go to Denver for surprising my friend on his birthday, so can you make a reservation with a connecting flight?

ASSISTANT: Sure. May I know when you are willing to travel?

USER: I want to ravel on 01/25 and return on 01/27.

ASSISTANT: Do you have price limit?

USER: My price limit is 500.

ASSISTANT: Could you please provide your airport codes?

USER: My airport codes are OAK and DEN.

ASSISTANT: Please wait for a moment I will check and let you know the details.

USER: Ok.

ASSISTANT: Sorry to say that there are no connecting flights available with your requirement.

USER: No problem, thank you.

ASSISTANT: Thank you for approaching us.