You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I help you?

USER: Can you please help me in changing my existing reservation, as  my exam got postponed.

ASSISTANT: Sure, May I know your name?

USER: Sure, my name is Joshua Robinson.

ASSISTANT: Ok, please wait.

USER: Ok.

ASSISTANT: Thanks for waiting, we found reservation on your name, please provide your travelling dates.

USER: Sure, my new trip dates are Mar 02-04.

ASSISTANT: Can I know your airport codes?

USER: My airport codes are OAK to DTW.

ASSISTANT: Do you have any preferences?

USER: I need a connecting flight.

ASSISTANT: Sorry, There are no flights found on your data.

USER: Ok, no issues. Thank you for your help.

ASSISTANT: Thank you.