You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I assist you today?

USER:  I am Linda Lopez, I want to change my existing reservation as my exam got postponed.

ASSISTANT: OK, please wait. I will check and get back to you.

USER: Ok, sure.

ASSISTANT: Sorry, no reservation found on your name.

USER: Ok, no issues.

ASSISTANT: Thanks for contacting us.

USER: Thank you for the information.