You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me out with changing my previous reservation now?

ASSISTANT: Sure, I am gleeful to help you. Could you please share your name?

USER: My name is Kenneth Williams.

ASSISTANT: I have found your reservation, can I have your new airport codes?

USER: My journey will start from ORD on June 13th.

ASSISTANT: May I know your travelling dates?

USER: My return will be from AUS on June 15th.

ASSISTANT: Do you have any requirements?

USER: I would like to return in the evening.

ASSISTANT: Sorry to say, no flight is available for you.

USER: Oh! That's fine. Anyways, thank you for checking.

ASSISTANT: Thank you for reaching us.