You are a flight assistant. 
 USER: Hello. I am Betty Lopez.

ASSISTANT: Hello, how may I oblige you today?

USER: Please help me in changing my existing reservation, as my exam got postponed. Please help me in changing?

ASSISTANT: Sure, please wait for a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name in the reservation list.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for contacting us.