You will have to create some sort of map file.

I.E.

OldPrinter = NewPrinter
OldPrinter2 = NewPrinter2
etc = etc

Once you have that, you can Enum the printers that are currently installed and retrieve the default while you are at it.

Now that you have all of the information about the old printers, you can delete them.

And finally you look at your map and see which printer is which and install the new one.
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