There is usually a way to disengage the female spade from inside the connector itself. A small jewelers screwdriver or the like that you can press on a small tab to release the spade from inside the connector. I've been able to undo the crimp on the existing wire (carefully) to salvage the spade connector, and then crimp on a new wire, and insert the spade back into the connector. Takes a light hand and patience with old connectors, but can be done. The plastic can get very brittle from age, and sometimes the spade "keeper" for lack of a better word can break off.