You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I heard that your agency gives quick service, I want to do some modifications in my previous reservation, can you please help me in modify the reservation?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Sorry, I did not find any reservation showing active in our database for updating your reservation.

USER: That really sad to hear. Thank you for your valuable information.

ASSISTANT: Welcome. Thank you for choosing us. May I know your name?

USER: Myself Carolyn Anderson.

ASSISTANT: Thank you.