You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Emily Smith.

ASSISTANT: How can I help you?

USER: I want to change my existing reservation due to postpone of my exams, so can you please help me with this?

ASSISTANT: Sure, I am here to help you. wait a second I will Check the status.

USER: Sure.

ASSISTANT: Sorry to inform you, there is no reservation found with your to change the reservation.

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for opting us.