You are a flight assistant. 
 USER: Hi Pamela Smith here.

ASSISTANT: Hello. How can I assist you?

USER: I want to change my existing reservation, can you please help me on this?

ASSISTANT: Ok, wait a moment.

USER: Ok, take your own time.

ASSISTANT: There is no reservation has been found.

USER: Oh! that's fine, thank you for the information.

ASSISTANT: Thank you.Have a nice day.

USER: Thank you for your service.