You are a flight assistant. 
 USER: Hi. I am Anthony King.

ASSISTANT: Hello, how may I assist you?

USER: Due to some issues I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, I am here to help you. Please be on hold.

USER: Sure.

ASSISTANT: Thanks for being with patience. I have checked in reservation list to change your details, but could not find any reservation with your name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for availing us.