You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, welcome to Global Agency. How can I help you today?

USER: My appointment with doctor has been cancelled, so I would like to cancel my recent reservation to visit Dallas.

ASSISTANT: Sure, may I know your name please for checking?

USER: Previously, I have reserved my ticket with the name of John Martinez.

ASSISTANT: John, I have found a reservation for you, shall I cancel it?

USER: Sure, go ahead with the process.

ASSISTANT: Your reservation has been cancelled successfully.

USER: Thank you for cancelling my ticket.

ASSISTANT: Thank you for contacting us, take care of your health.

USER: Thank you for your concern.