You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Due to sudden changes, my exams has been postponed. Can you please help me to change my existing reservation?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: I need your name to check the existing reservation.

USER: George Lewis here.

ASSISTANT: Give me a minute, I will let you know the status.

USER: Ok.

ASSISTANT: Thank you for waiting, we found a reservation on your name. Can you please share your updated journey dates?

USER: My new journey dates will be on June 15 to June 17.

ASSISTANT: May I know your boarding and landing airport codes?

USER: I want to start from MSP and return from DCA.

ASSISTANT: Let me know your connection limit.

USER: I want to travel in a connecting flight.

ASSISTANT: Do you have any airline preference?

USER: I would like to prefer a well known airlines.

ASSISTANT: In which class would you like me to book your ticket?

USER: I am comfortable with any class.

ASSISTANT: Please, wait for a while.

USER: Sure.

ASSISTANT: I am sorry to inform you that, there were no flights available that matches your requirements.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for approaching us.