You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello,how may I help you?

USER: My name is Lisa Wilson, am not feeling well, so I want to change my existing reservation.

ASSISTANT: Ok, Please wait for a while. Sorry, there is no reservation found on your name.

USER: Ok, not an issue. Thank you, for your service.

ASSISTANT: Thank you for reaching us,Take care.

USER: Thank you.