You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my existing reservation because I have to stay for some more days with my grandfather, can you please help me?

ASSISTANT: Ok, please provide your name to check your reservation.

USER: Sure, my name is Andrew Perez.

ASSISTANT: Please wait a moment, let me check.

USER: Sure.

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

USER: No problem, thank you for the information.

ASSISTANT: welcome, have a nice day.