You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to change my reservation due to sudden change in my trip. can you assist me?

ASSISTANT: Sure, may I know your name?

USER: Katherine Brown.

ASSISTANT: Wait a minute.

USER: Sure.

ASSISTANT: There was no reservation found on your name.

USER: No problem, thank you for searching.

ASSISTANT: Thank you for choosing us.