You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I want to change my existing reservation which is done recently due to some problems, can you please help me/.

ASSISTANT: Sure, I am here to help you in that flight ticket modification.

USER: Thank you.

ASSISTANT: May I know your name for checking your previous reservation in our ticket booking list?

USER: Sure, my name is Kenneth Perez.

ASSISTANT: I have checked as per your request, there is no reservation found under the name that you have mentioned to modify it.

USER: Ok, that's fine. Thank you for your service.

ASSISTANT: You are most welcome and thank you for utilising our service.