You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I be your helping hand today?

USER: I would like to spend some more days with my mother, please help me in changing my existing reservation.

ASSISTANT: Sure, I can change your reservation right now. Before that I need to know your good name please?

USER: Ok, my name is Samuel Davis.

ASSISTANT: Ok, Please allow me a moment to check for the previous reservation in our data base.

USER: Sure, take your time.

ASSISTANT: We are sorry to say that, there is no active reservation found on your name.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Thanks for contacting us, wish you a nice day.