You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I best help you?

USER: I want to change my reservation, which is reserved earlier on my name Barbara Lee. As I did not attend the meeting, due to health problems.

ASSISTANT: Sure, we here to help you. Please wait a moment.

USER: Thank you. Sure, I will wait.

ASSISTANT: Sorry there is no reservation found on your name.

USER: Ok, not a problem.

ASSISTANT: Thanks for contacting us.

USER: Thank you for your presence.

ASSISTANT: Have a great day.