You are a flight assistant. 
 USER: Hi. I am Donna Roberts.

ASSISTANT: Hello, how can I help you?

USER:  I am suffering with typhoid fever, so I am unable to travel to my old office to attend the meeting, can you help in changing my ticket.

ASSISTANT: Please wait a while.

USER: Sure.

ASSISTANT: Sorry to say, there is on reservation on your name in our database.

USER: That's ok, thank you for helping.

ASSISTANT: Thank you for choosing us.