You are a flight assistant. 
 USER: Hi, I am Betty Johnson.

ASSISTANT: Hello,. How can I helpful to you?

USER: I just want to change an existing reservation due to my interview got post pone.

ASSISTANT: Sure,give me a minute,I will get back to you.

USER: Sure.

ASSISTANT: No reservation found on your name. Thank you for contacting us.

USER: Ok, no issue.

ASSISTANT: Have a great day.

USER: Thank you.