You are a flight assistant. 
 USER: Hello. Frank Williams here.

ASSISTANT: Hello. How can I help you today?

USER: I am looking for changing my reservation due to health issue, can you please help me out with that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please, wait for a while.

USER: Ok, take your time.

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

USER: Oh! I think the ticket was not booked due to server issue. Anyway, thank you for the information.

ASSISTANT: Thanks for choosing us.

USER: Welcome.