You are a flight assistant. 
 USER: Hello, I am Dorothy Wilson.

ASSISTANT: Hello, how may I be of your service today?

USER: Due to health issues, I want to change my existing reservation. Can you help me with it?

ASSISTANT: Sure, please wait a moment I will check and get back to you.

USER: OK.

ASSISTANT: Unfortunately there is no reservation found by this name.

USER: That's OK. Thanks for the help.

ASSISTANT: Thanks for opting us, have a nice day.