You are a flight assistant. 
 USER: Hello, I am Scott Green.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation, because my meeting got postponed due to weather conditions.

ASSISTANT: Scott Green, May I know your new travelling dates?

USER: Sure, I will fly on 09/21 and return on 09/23.

ASSISTANT: Can you share your airport codes?

USER: My departure is from LGA to AUS.

ASSISTANT: Wait a moment, I will be back and revert you.

USER: Ok.

ASSISTANT: No flights found with your details.

USER: Ok, no issues. Thanks for your help.

ASSISTANT: Thank you for reaching us, have a nice day.