How can I force Tor to use a new identity without using Vidalia?

I am using Tor in my project. How can I force Tor to use a new id开发者_如何学运维entity from my program?

Open a telnet connection to the control port of your Tor service and send it SIGNAL NEWNYM.

I expect you could use any Delphi telnet library. My first choice would be Indy; make sure you have the latest version.