You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Gary Turner, want to alter my reservation dates, Can you please help me?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Gary, we found your reservation. Please share your airport codes.

USER: My airport codes are from DEN to MSP.

ASSISTANT: Can I know your trip dates?

USER: My trip dates are from 12/08 to 12/10.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Thanks for waiting and there is no flight available as per your request.

USER: It's ok, thank you.

ASSISTANT: Most welcome.