You are a flight assistant. 
 USER: Hello, I am Andrew White.

ASSISTANT: Hello, how can I assist you?

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

ASSISTANT: Sure, Please wait.

USER: Ok.

ASSISTANT: Thanks for waiting, no reservation found with your name.

USER: That's ok.

ASSISTANT: Thank you for choosing our service.