You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I am Dorothy White. Actually, I didn't found the option of change reservation. Can you do this for me?

ASSISTANT: Sure, give me  a minute.

USER: Ok.

ASSISTANT: There is a reservation on your name, can I know your new journey dates?

USER: Yes, sure. I want to change my airport codes and my airport code are from SFO to DEN.

ASSISTANT: Ok, can you share your dates of journey?

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

ASSISTANT: Sorry, there is no flight found on your requested dates.

USER: That's fine.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your help.