You are a flight assistant. 
 USER: Hello. Karen Evans here.

ASSISTANT: Hello, how can I assist you for the day?

USER: I want to change my existing reservation due to some health issues, can you help me in doing that?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait a minute, I will check your reservation status and get back to you.

USER: Sure, take your time.

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

USER: Ok, no issues. Thank you for the information.

ASSISTANT: Thank you for availing us.