You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation, as my exam has postponed. Can you please help me with this?

ASSISTANT: Sure, may I know your name please?

USER: I am Joseph Anderson.

ASSISTANT: Sure, may I know your airport codes?

USER: My airport codes are DEN and IAD.

ASSISTANT: Ok, may I know your travelling dates?

USER: I prefer to travel on 09/22 and 09/24. Please make sure that the connection is 1.

ASSISTANT: Sorry, there is no plane with 1 connection.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for opting us, have a great day.