You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I want to change my existing reservation. Can you please help me in that?

ASSISTANT: Sure, will you mention your name for checking the reservation status?

USER: Myself Catherine Johnson.

ASSISTANT: Your reservation is found. Please provide your airport codes.

USER: My airport codes are DTW to AUS.

ASSISTANT: Please mention your travelling dates.

USER: I will start my journey on July 23 and return on July 25.

ASSISTANT: Do you have any specifications?

USER: I need a connecting flight.

ASSISTANT: Do you have any other preferences?

USER: No, I don't have any other specifications.

ASSISTANT: There are no flights found under your preferable details.

USER: Ok, no problem. Thank you.

ASSISTANT: Welcome, have a great day.