You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: Can you please change my existing reservation?

ASSISTANT: Sure, may I know your name?

USER: Sure, My name is Mary Hall.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found on your name.

USER: Ok, No issues.

ASSISTANT: Thank you for choosing us.

USER: Thank you.