You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may i assist you?

USER: I want to change my existing reservation which is with the name Amanda Walker. Please help me out.

ASSISTANT: Sure, let me check the current status and get back to you.

USER: Ok.

ASSISTANT: Thanks for being patient. It's unfortunate that we could not find any reservation by this name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.