You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Due to change in my plans to visit Dallas, can you please help me by changing the existing reservation?

ASSISTANT: Sure, may I know your name to check for the previous reservation?

USER: My previous reservation has done with name Kenneth Lopez.

ASSISTANT: Please allow me a moment to check for the previous reservation.

USER: Sure, take your own time.

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

USER: Ok, not an issue. May be something went wrong while booking the ticket. Thank you for providing information.

ASSISTANT: Thank you for contacting us.