You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Due to sudden work, I want to alter my reservation. Can you please help me with it?

ASSISTANT: Sure, I am here to help you out. May I know your name please?

USER: Dorothy Clark here.

ASSISTANT: Wait a moment please.

USER: Ok.

ASSISTANT: Dorothy Clark, we haven't found any reservation under your name in our database.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for choosing us.