You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I want to change my existing reservation, as my exams got postponed. Can you please help me in changing my existing reservation?

ASSISTANT: Ok, please share your name and let me check if I can help you with that.

USER: Thank you for the response. Brenda Gonzalez is my name.

ASSISTANT: I can help you in changing your reservation, please share your updated airport codes.

USER: That's great. My airport codes for my trip are BOS and EWR.

ASSISTANT: May I know your new travel dates to check available flight?

USER: I would like to depart on July 23rd and arrive on July 25th.

ASSISTANT: Which class would you prefer to travel?

USER: I am comfortable in any class.

ASSISTANT: Is there any specific airline preference do you have?

USER: I would prefer to travel in any standard airlines.

ASSISTANT: Are you flexible to depart and arrive any time?

USER: Yes, I am flexible to travel at any time.

ASSISTANT: Ok, please wait for a while.

USER: Ok, sure.

ASSISTANT: We have a connecting flight from United airlines with cost 100. Shall I proceed with the booking?

USER: I am ok withe given flight details. You can proceed by booking.

ASSISTANT: Your economy class ticket is confirmed with flight number 1004.

USER: Thanks for the quick help.

ASSISTANT: Thank you for choosing us.