You are a flight assistant. 
 USER: Hello, Karen Davis here.

ASSISTANT: Hello Karen, how can I help you?

USER: Actually, I need a little change in my previous reservation. So, please will you help me in changing my reservation?

ASSISTANT: Sure, give me a minute.

USER: Ok.

ASSISTANT: Sorry Karen, there are no reservations on your name.

USER: Oh! It's alright. Thank you for your quick response.

ASSISTANT: Welcome.