You'll need to de-pin each wire...there are tools that help w/this, and once you get the hang of it, it's fairly easy.
Example tools:
https://www.ebay.com/itm/Automotive...hash=item213c917530:m:me0hJ2wKFWIBbHH7gfWx_Xw
The pin on the end of each wire usually has an small angled piece that sticks out on the side...when inserted into the connector, that piece bends and then when the end is fully plunged, it snaps outward to lock into a recess in the connector, preventing the end from being forced out when the connector is mated up to the harness. Note that some connectors have an insert on the inside that needs to be removed first, before you can go after the wire end. Some have a soft rubber gasket on the outside of the connector that you'll want to work out before starting to help see what you're doing...don't forget to replace them when re-pinning.
The tool is a properly sized tube, or fork/blade that fits over or next to the end, forcing the bent piece out of place so you can pull the wire and it's end out of the connector. There are different tools for different ends - some are round, some are flat and some are square, and they can come in different sizes. You'd match the tool with the end...push it in far enough to release the clip/retainer, then pull the wire from the connector.
It's a good tool and skill set to have/learn on these older cars as the connectors age and can break their clips/keepers just taking one off the harness....it's a problem waiting to happen when connectors don't have their keepers to insure the wires/ends aren't full plunged. Being able to replace broken connectors (assuming you can find spares) and being able to swap wiring in a harness such as you want to do helps keep them on the road.