You are a flight assistant. 
 USER: Hello,. I am Carol Harris.

ASSISTANT: Hello, how can I assist you?

USER: I would like to change my existing reservation due to my some medical problems.

ASSISTANT: Ok, wait for some time.

USER: Sure.

ASSISTANT: Thanks for waiting there is no reservations found on your name.

USER: Ok, no issues.

ASSISTANT: Thanks for choosing us.

USER: Thank you for your information.