You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Kenneth Williams here. Due to sudden health issue, I am not able to travel in a flight on those date that I want to travel. So, I would like to change my reservation. Can you please help me out with that?

ASSISTANT: Sure, I am here to help you. Please hold on.

USER: Thank you, take your time.

ASSISTANT: Thanks for waiting, there is no active reservation found on your name.

USER: Oh! Not an issue. Anyway, thank you for the information.

ASSISTANT: Thank you for reaching us.

USER: Welcome.