You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: I would like to meet my childhood friend after a long time at St. Paul MN-MSP, could you help me with booking a ticket on 03/21?

ASSISTANT: Sure, May I know the source code?

USER: My takeoff airport code is  Co-DEN.

ASSISTANT: Please help me with your return date.

USER: I intend to return on 03/23.

ASSISTANT: May I know your name?

USER: John Thomas here.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Sorry, No flights found with your chosen dates. Thank you for opting us.

USER: Ok, not a problem. Thank you.