How to convert a 4 wire O2 harness to a 3 wire setup

[headstrong]

I need to replace my rear O2 sensor on my 1995 240SX and have parts from a 1997 car. I need to splice and replace both the connector and O2 sensor since my original connector was ripped off the harness during an accident along with my entire exhaust. Has anyone done this before or can talk me through it? My 95 has 3 wires (red, black & orange) while the connectors I'm modifying has two white and two black wires. Thanks for any assistance.

James