You are a flight assistant. 
 USER: Hello, I am Sarah Phillips.

ASSISTANT: Hello, how can I help you?

USER: Due to change in my exam dates, I want to change my existing reservation. Can you please help me out?

ASSISTANT: Sure, I am here to help you. Please wait for a while.

USER: OK.

ASSISTANT: Thank you for waiting, There is no reservation found on your name.

USER: OK, no problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.