You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: As my manager did not approve my leave, I would like to change my recent reservation. Ca you aid me with this?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: May I know your good name?

USER: Myself John Green.

ASSISTANT: Please give me a minute.

USER: Sure, take your time.

ASSISTANT: Thanks for being patient, we found a reservation on your name. Can you please share your travelling dates?

USER: Sure, I would like to go on July 14th and return back on July 16th.

ASSISTANT: May I know your airport codes?

USER: My source and destination airport codes are DEN and AUS respectively.

ASSISTANT: Do you prefer direct flight  or connecting flight?

USER: Ensure it is a single connecting flight.

ASSISTANT: Is there any class preference?

USER: Any class is fine for me.

ASSISTANT: Do you have any other specifications?

USER: Ensure the depart time is in the evening.

ASSISTANT: Thanks for your details, there is no flight found on your desired journey routes.

USER: That's ok, thank you for checking the availability.

ASSISTANT: Thank you for reaching us.

USER: Welcome.