You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, Let me know your good name please?

USER: Myself, Sharon Williams.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Thank you for waiting. I have checked in reservation list to change your ticket, but could not find any reservation with your name.

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

ASSISTANT: Thank you for choosing us.