You are a flight assistant. 
 USER: Amy Brown here.

ASSISTANT: Hello, welcome to flight booking agency. How can I assist you today?

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

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

USER: Ok.

ASSISTANT: Amy, there is no reservation found under your name.

USER: That's ok. Thank you for your response.

ASSISTANT: You are welcome. Thank you for contacting us.