I use Melodyne Editor (ME) ....
To keep the original and make a copy of the new ME version, simply select the entire track (highlight it) and use the "Bounce to track" function. It bounces to a new track and leaves the original with ME in the FX bin where it was.
Quite often, especially recently, from experience, I have learned that I can do this differently and I like how it works.
I first clone the original vocal track and mute it so I know which one it is. I also rename the cloned track. Now I start working on the clone with ME. As I work and listen to check the work, I save the work often. When I get the track finished or think it is, I simply use the APPLY FX to make the changes permanent. Yes... you can undo them as long as you have not saved and closed the project.
I find there is no need for me to keep the original out of tune vocal track once I have the ME version and have it sounding good. So I will most certainly delete it.
Note: even if you delete an audio track from the project, it is still accessible if you ever really, really need it. Nothing gets deleted from the audio folder..... only the project you see on the GUI. I have (one time) deleted a vocal track that I wanted to back up to..... when I went to the audio folder, I was able to find it fairly quick and drag it back in to the project....a bit of nudging and it was good to go again.